WO2022175781A1

WO2022175781A1 - Display device, display module, and electronic apparatus

Info

Publication number: WO2022175781A1
Application number: PCT/IB2022/051089
Authority: WO
Inventors: 山崎舜平; 岡崎健一; 江口晋吾; 方堂涼太
Original assignee: 株式会社半導体エネルギー研究所
Priority date: 2021-02-19
Filing date: 2022-02-08
Publication date: 2022-08-25
Also published as: JPWO2022175781A1; CN116868693A; KR20230147648A; US20240099068A1

Abstract

Provided is a high-definition display device. The present invention comprises a first and second light emitting device, a first and second colored layer, and a first, second, and third insulator, wherein: the first colored layer is disposed so as to overlap the first light emitting device; the second colored layer is disposed so as to overlap the second light emitting device; the first light emitting device and the second light emitting device have the function of emitting white light; the first colored layer has the function of transmitting visible light of a color differing from that of the second colored layer; the first light emitting device has a first conducting layer and a first light-emitting layer on the first conducting layer; the second light emitting device has a second conducting layer and a second light-emitting layer on the second conducting layer; the first insulator is in contact with at least part of a side surface of the first light emitting device; the second insulator is in contact with at least part of a side surface of the second light emitting device; the first insulator and the second insulator are disposed on the third insulator; and the third insulator is disposed so as to cover an end of the first conducting layer and an end of the second conducting layer.

Description

Display device, display module, and electronic device

One aspect of the present invention relates to a display device, a display module, and an electronic device. One embodiment of the present invention relates to a method for manufacturing a display device.

It should be noted that one aspect of the present invention is not limited to the above technical field. Technical fields of one embodiment of the present invention include semiconductor devices, display devices, light-emitting devices, power storage devices, memory devices, electronic devices, lighting devices, input devices (e.g., touch sensors), and input/output devices (e.g., touch panels). ), how they are driven, or how they are manufactured.

In recent years, information terminal devices such as mobile phones such as smartphones, tablet information terminals, and notebook PCs (personal computers) have become widespread. High-definition display panels are required for the display panels provided in these devices.

Display devices that can be applied to display panels typically include liquid crystal display devices, organic EL (Electro Luminescence) elements, light-emitting devices equipped with light-emitting elements such as light-emitting diodes (LEDs), and electrophoretic display devices. Examples include electronic paper that performs display by, for example.

For example, the basic structure of an organic EL device is to sandwich a layer containing a light-emitting organic compound between a pair of electrodes. By applying a voltage to this device, light can be obtained from the light-emitting organic compound. A display device to which such an organic EL element is applied does not require a backlight, which is required in a liquid crystal display device or the like. For example, Patent Document 1 describes an example of a display device using an organic EL element.

JP-A-2002-324673

An object of one embodiment of the present invention is to provide a high-definition display device. An object of one embodiment of the present invention is to provide a high-resolution display device. An object of one embodiment of the present invention is to provide a display device with a high aperture ratio. An object of one embodiment of the present invention is to provide a highly reliable display device. An object of one embodiment of the present invention is to provide a method for manufacturing the display device.

The description of these issues does not prevent the existence of other issues. One aspect of the present invention does not necessarily have to solve all of these problems. Problems other than these can be extracted from the descriptions of the specification, drawings, and claims.

One embodiment of the present invention includes a first light-emitting device, a second light-emitting device, a first colored layer, a second colored layer, a first insulator, a second insulator, and a second insulator. 3 insulators, wherein the first colored layer is disposed overlying the first light emitting device, the second colored layer is disposed overlying the second light emitting device, and the first and the second light emitting device have a function of emitting white light, the first colored layer has a function of transmitting visible light of a color different from that of the second colored layer, and the first has a first conductive layer and a first light emitting layer on the first conductive layer, and the second light emitting device has a second conductive layer and on the second conductive layer wherein the first insulator is in contact with at least part of the side surface of the first light emitting device, and the second insulator is in contact with at least one side surface of the second light emitting device A first insulator and a second insulator are disposed over a third insulator, the third insulator contacting the ends of the first conductive layer and the second conductive layer. a display device placed over the edge of the

In the above, the first light-emitting layer and the second light-emitting layer may have the same material.

In the above, the first light emitting device includes a first light emitting unit including a first light emitting layer, a first charge generation layer on the first light emitting unit, and a second charge generation layer on the first charge generation layer. a light-emitting unit, the second light-emitting unit having a third light-emitting layer, the second light-emitting device comprising a third light-emitting unit including the second light-emitting layer; and a third light-emitting unit. It preferably has a second charge generating layer on top and a fourth light emitting unit on the second charge generating layer, the fourth light emitting unit having a fourth light emitting layer. In the above, the first light-emitting unit contains the same material as the third light-emitting unit, the first charge-generation layer contains the same material as the second charge-generation layer, and the first charge-generation layer contains the same material as the second charge-generation layer. The second light emitting unit may have the same material as the fourth light emitting unit.

In the above, the first light-emitting unit includes the first hole-injection layer, the first hole-transport layer, and the first electron-transport layer, and the second light-emitting unit includes the second a hole-transporting layer and a second electron-transporting layer, the third light-emitting unit comprising the second hole-injecting layer, the third hole-transporting layer, and the third electron-transporting layer; , the fourth light-emitting unit has a fourth hole-transporting layer and a fourth electron-transporting layer, the first insulator laterally of the first hole-injecting layer; First hole-transport layer side, first light-emitting layer side, first electron-transport layer side, first charge generation layer side, second hole-transport layer side, third light emission The second insulator contacts the side of the layer and the side of the second electron-transporting layer, and the second insulator is on the side of the second hole-injecting layer, the side of the third hole-transporting layer, and the side of the second light-emitting layer. , the side of the third electron-transporting layer, the side of the second charge generating layer, the side of the fourth hole-transporting layer, the side of the second light-emitting layer, and the side of the fourth electron-transporting layer. is preferred.

In the above, the first insulator and the second insulator have a first layer and a second layer on the first layer, and in the first insulator, the first layer the side surface of the first layer contacts at least a portion of the side surface of the first light emitting device, the bottom surface of the first layer contacts at least a portion of the third insulator, and the side surface and bottom surface of the second layer contact the first in contact with at least part of the layer of the second insulator, the side surface of the first layer contacts at least part of the side surface of the second light-emitting device, and the lower surface of the first layer is in contact with the third insulator Preferably, it is in contact with at least part of the body and the side and bottom surfaces of the second layer are in contact with at least part of the first layer. Moreover, in the above, it is preferable that the first layer contains aluminum oxide and the second layer contains silicon nitride.

In the above, the side surface of the first light-emitting layer and the side surface of the second light-emitting layer face each other, and the distance between the side surface of the first light-emitting layer and the side surface of the second light-emitting layer is 8 μm or less. is preferably.

One aspect of the present invention is a display module having a display device having any of the above configurations, and a connector such as a flexible printed circuit (hereinafter referred to as FPC) or TCP (tape carrier package) attached. , or a display module such as a display module in which an integrated circuit (IC) is mounted by a COG (Chip On Glass) method, a COF (Chip On Film) method, or the like.

An aspect of the present invention is an electronic device including the display module described above and at least one of a housing, a battery, a camera, a speaker, and a microphone.

A high-definition display device can be provided according to one embodiment of the present invention. One embodiment of the present invention can provide a high-resolution display device. According to one embodiment of the present invention, a display device with a high aperture ratio can be provided. One embodiment of the present invention can provide a highly reliable display device. One embodiment of the present invention can provide a method for manufacturing the display device.

The description of these effects does not prevent the existence of other effects. One aspect of the present invention does not necessarily have all of these effects. Effects other than these can be extracted from the descriptions of the specification, drawings, and claims.

FIG. 1A is a top view showing an example of a display device. FIG. 1B is a cross-sectional view showing an example of a display device;
2A and 2B are cross-sectional views showing an example of a display device.
3A and 3B are cross-sectional views showing an example of a display device.
4A to 4E are top views showing examples of pixels of a display device.
FIG. 5A is a top view showing an example of a display device. FIG. 5B is a cross-sectional view showing an example of a display device;
6A to 6G are top views showing examples of pixels of a display device.
7A and 7B are cross-sectional views showing an example of a display device.
8A and 8B are cross-sectional views showing an example of a display device.
9A and 9B are cross-sectional views showing an example of a display device.
10A to 10D are diagrams illustrating an example of a method for manufacturing a display device.
11A to 11C are diagrams illustrating an example of a method for manufacturing a display device.
12A to 12C are diagrams illustrating an example of a method for manufacturing a display device.
13A and 13B are diagrams illustrating an example of a method for manufacturing a display device.
FIG. 14 is a perspective view showing an example of a display device.
FIG. 15A is a cross-sectional view showing an example of a display device; 15B and 15C are cross-sectional views showing examples of transistors.
FIG. 16 is a cross-sectional view showing an example of a display device.
17A and 17B are diagrams showing configuration examples of the display module.
FIG. 18 is a diagram illustrating a configuration example of a display device.
FIG. 19 is a diagram illustrating a configuration example of a display device.
FIG. 20 is a diagram illustrating a configuration example of a display device.
21A and 21B are diagrams illustrating examples of electronic devices.
22A to 22D are diagrams illustrating examples of electronic devices.
23A to 23F are diagrams illustrating examples of electronic devices.

The embodiment will be described in detail using the drawings. However, the present invention is not limited to the following description, and those skilled in the art will easily understand that various changes can be made in form and detail without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the descriptions of the embodiments shown below.

In addition, in the configuration of the invention described below, the same reference numerals are used in common for the same parts or parts having similar functions in different drawings, and repeated description thereof will be omitted. Moreover, when referring to similar functions, the hatch patterns may be the same and no particular reference numerals may be attached.

In addition, the position, size, range, etc. of each configuration shown in the drawings may not represent the actual position, size, range, etc. for ease of understanding. Therefore, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings.

It should be noted that the terms "film" and "layer" can be interchanged depending on the case or situation. For example, the term "conductive layer" can be changed to the term "conductive film." Alternatively, for example, the term “insulating film” can be changed to the term “insulating layer”.

(Embodiment 1)
In this embodiment, a display device of one embodiment of the present invention and a manufacturing method thereof will be described with reference to FIGS.

In the display device of one embodiment of the present invention, pixels are arranged in matrix in the display portion, and an image can be displayed on the display portion. The pixel has a light-emitting device that emits white light and a colored layer that overlaps the light-emitting device. Full-color display can be performed by using colored layers that transmit visible light of different colors in each pixel. Furthermore, since the light emitting device used for each pixel can be formed using the same material, the manufacturing process can be simplified and the manufacturing cost can be reduced.

As the light emitting device, it is preferable to use EL devices such as OLED (Organic Light Emitting Diode) and QLED (Quantum-dot Light Emitting Diode). Examples of light-emitting substances that EL devices have include substances that emit fluorescence (fluorescent materials), substances that emit phosphorescence (phosphorescence materials), inorganic compounds (quantum dot materials, etc.), and substances that exhibit heat-activated delayed fluorescence (heat-activated delayed fluorescence (Thermally Activated Delayed Fluorescence: TADF) material). Moreover, LEDs, such as micro LED (Light Emitting Diode), can also be used as a light emitting device.

When the light-emitting device of each pixel is formed of a white-light-emitting organic EL device, it is not necessary to separate the light-emitting layers in each pixel. Therefore, a layer other than the pixel electrode included in the light-emitting device (for example, a light-emitting layer) can be shared by each pixel. However, among the layers included in the light-emitting device, there are also layers with relatively high conductivity. Leakage current may occur between pixels when a layer with high conductivity is commonly provided for each pixel. In particular, when a display device has a high definition or a high aperture ratio and the distance between pixels becomes small, the leakage current becomes unignorable, and there is a possibility that the display quality of the display device is deteriorated. Therefore, in a display device according to one embodiment of the present invention, at least part of a light-emitting device in each pixel is formed in an island shape, so that the display device has high definition. Here, it is assumed that the island-shaped portion of the light-emitting device includes a light-emitting layer.

For example, an island-shaped light-emitting layer can be formed by a vacuum deposition method using a metal mask (also called a shadow mask). However, in this method, island-like formations occur due to various influences such as precision of the metal mask, misalignment between the metal mask and the substrate, bending of the metal mask, and broadening of the contour of the deposited film due to vapor scattering. Since the shape and position of the light-emitting layer deviate from the design, it is difficult to increase the definition and aperture ratio of the display device.

In a method for manufacturing a display device of one embodiment of the present invention, an island-shaped pixel electrode (which can also be called a lower electrode) is formed, and a layer including a light-emitting layer (which can be called an EL layer or part of an EL layer) is formed. After forming all over, a sacrificial layer is formed on the EL layer. Then, an island-shaped EL layer is formed by forming a resist mask over the sacrificial layer and processing the EL layer and the sacrificial layer using the resist mask. Note that the sacrificial layer may be referred to as a mask layer in this specification and the like.

As described above, in the method for manufacturing a display device of one embodiment of the present invention, the island-shaped EL layer is not formed by a pattern of a metal mask, but is formed by forming an EL layer over one surface and then processing the EL layer. be done. Therefore, it is possible to realize a high-definition display device or a display device with a high aperture ratio, which has hitherto been difficult to achieve. Further, by providing the sacrificial layer over the EL layer, damage to the EL layer during the manufacturing process of the display device can be reduced, and the reliability of the light-emitting device can be improved.

It is difficult to reduce the distance between adjacent light emitting devices to less than 10 μm by, for example, a formation method using a metal mask. , can be narrowed down to 1 μm or less. Furthermore, by using an exposure apparatus for LSI, for example, the gap can be narrowed to 500 nm or less, 200 nm or less, 100 nm or less, or even 50 nm or less.

Also, the pattern of the EL layer itself (which can be said to be a processing size) can also be made much smaller than when a metal mask is used. In addition, for example, when a metal mask is used for different formation of the EL layer, the thickness of the EL layer varies between the center and the edge, so the effective area that can be used as the light emitting region is smaller than the area of the EL layer. Become. On the other hand, in the above manufacturing method, since the pattern is formed by processing a film formed to have a uniform thickness, the thickness can be made uniform within the pattern, and even if the pattern is fine, almost the entire area of the pattern can emit light. It can be used as a region. Therefore, a display device having both high definition and high aperture ratio can be manufactured.

Note that in a light-emitting device that emits white light, it is not necessary to form all the layers constituting the EL layer in an island shape, and some of the layers can be formed in the same process. In the method for manufacturing a display device of one embodiment of the present invention, after some layers forming the EL layer are formed in an island shape for each pixel, the sacrificial layer is removed, and the remaining layers forming the EL layer (for example, carrier injection layer, etc.) and a common electrode (which can also be called an upper electrode) can be formed in common.

On the other hand, the carrier injection layer is often a layer with relatively high conductivity in the light-emitting device. Therefore, the light-emitting device may be short-circuited when the carrier injection layer comes into contact with the side surface of the island-shaped EL layer. Note that even in the case where the carrier injection layer is provided in an island shape and only the common electrode is formed in common among the light emitting devices, the common electrode and the side surface of the island-shaped EL layer or the side surface of the pixel electrode should be in contact with each other. and the light-emitting device may short out.

Therefore, in the display device of one embodiment of the present invention, a sidewall insulator is provided in contact with the side surface of the island-shaped EL layer and a bank-shaped insulator is provided to cover the end portion of the island-shaped pixel electrode. to This can prevent the island-shaped EL layer from contacting the carrier injection layer or the common electrode. Therefore, short-circuiting of the light-emitting device can be suppressed, and the reliability of the light-emitting device can be improved.

[Configuration example of light-emitting device]
Here, configuration examples of the light-emitting device and the colored layer will be described with reference to FIGS. 2 and 3. FIG.

A schematic cross-sectional view of the display device 500 is shown in FIG. 2A. The display device 500 has a plurality of light emitting devices 550W that emit white light, and a colored layer 545R that transmits red light, a colored layer 545G that transmits green light, and a colored layer 545G that transmits green light are formed on each of the light emitting devices 550W. Alternatively, a coloring layer 545B that transmits blue light is provided. Here, the colored layer 545R, the colored layer 545G, and the colored layer 545B are preferably provided over the light-emitting device 550W with the protective layer 540 interposed therebetween.

The light-emitting device 550W has a structure in which two light-emitting units (light-emitting unit 512Q_1 and light-emitting unit 512Q_2) are stacked via an intermediate layer 531 between a pair of electrodes (electrodes 501 and 502).

The electrode 501 functions as a pixel electrode and is provided for each light emitting device. The electrode 502 functions as a common electrode and is commonly provided for a plurality of light emitting devices.

The light-emitting unit 512Q_1 includes

layers

521, 522, a light-emitting layer 523Q_1, a layer 524, and the like. The light-emitting unit 512Q_2 includes a layer 522, a light-emitting layer 523Q_2, a layer 524, and the like. In addition, the light-emitting device 550W has a layer 525 and the like between the light-emitting unit 512Q_2 and the electrode 502. FIG. Note that the layer 525 can also be considered part of the light emitting unit 512Q_2.

The layer 521 has, for example, a layer (hole injection layer) containing a highly hole-injecting substance. The layer 522 includes, for example, a layer containing a substance with a high hole-transport property (hole-transport layer). The layer 524 includes, for example, a layer containing a highly electron-transporting substance (electron-transporting layer). The layer 525 includes, for example, a layer containing a highly electron-injecting substance (electron-injection layer).

Alternatively, the layer 521 may have an electron-injection layer, the layer 522 may have an electron-transport layer, the layer 524 may have a hole-transport layer, and the layer 525 may have a hole-injection layer.

Although the layer 521 and the layer 522 are separately shown in FIG. 2A, the layers are not limited to this. For example, when the layer 521 has a function of both a hole-injection layer and a hole-transport layer, or when the layer 521 has a function of both an electron-injection layer and an electron-transport layer , the layer 522 may be omitted.

Further, the intermediate layer 531 has a function of injecting electrons into one of the light-emitting unit 512Q_1 and the light-emitting unit 512Q_2 and injecting holes into the other when a voltage is applied between the electrode 501 and the electrode 502. . The intermediate layer 531 can also be called a charge generation layer.

As the intermediate layer 531, for example, a material applicable to an electron injection layer, such as lithium fluoride, can be suitably used. Moreover, as the intermediate layer, for example, a material applicable to the hole injection layer can be preferably used. In addition, a layer containing a material with high hole-transport properties (hole-transport material) and an acceptor material (electron-accepting material) can be used for the intermediate layer. In addition, a layer containing a highly electron-transporting material (electron-transporting material) and a donor material can be used for the intermediate layer. By forming an intermediate layer having such a layer, it is possible to suppress an increase in drive voltage when light emitting units are stacked.

By making the luminescent color of the luminescent layer 523Q_1 and the luminescent color of the luminescent layer 523Q_2 of the light emitting device 550W have a complementary color relationship, the light emitting device 550W can be a light emitting device that emits white light. The light-emitting layers 523Q_1 and 523Q_2 preferably contain light-emitting substances that emit light such as R (red), G (green), B (blue), Y (yellow), and O (orange). Alternatively, the light emitted from the light-emitting substances included in the light-emitting layers 523Q_1 and 523Q_2 preferably includes spectral components of two or more of R, G, and B colors.

Here, an example of a combination of luminescent colors of the luminescent layers of the luminescent units that can be used in the luminescent device 550W will be described.

For example, when the light-emitting device 550W has two light-emitting units, one light-emitting unit emits red and green light, and the other light-emitting unit emits blue light, thereby obtaining the light-emitting device 550W that emits white light. . Alternatively, by obtaining yellow or orange light emission from one light emitting unit and blue light emission from the other light emitting unit, the light emitting device 550W that emits white light can be obtained.

Further, for example, when the light-emitting device 550W has three light-emitting units, red light is emitted from any one light-emitting unit, green light is emitted from the other light-emitting unit, and blue light is emitted from the remaining light-emitting unit. Thus, a light-emitting device 550W that emits white light can be obtained. Further, a light-emitting layer emitting blue light is used in the first light-emitting unit, a light-emitting layer emitting yellow light, yellow-green light, or green light is used in the second light-emitting unit, and a light-emitting layer emitting blue light is used in the third light-emitting unit. can be used. Further, the first light-emitting unit uses a blue light-emitting layer, and the second light-emitting unit uses a stacked structure of a red light-emitting layer and a yellow, yellow-green, or green light-emitting layer, A light-emitting layer emitting blue light can be used for the third light-emitting unit.

Further, for example, when the light-emitting device 550W has four light-emitting units, a light-emitting layer emitting blue light is used for the first light-emitting unit, and one of the second light-emitting unit and the third light-emitting unit emits red light. A yellow-, yellow-green-, or green-emitting layer can be used for the other, and a blue-emitting layer can be used for the fourth light-emitting unit.

By providing the colored layer 545R, the colored layer 545G, or the colored layer 545B on the light emitting device 550W capable of emitting white light, each pixel emits red light, green light, or blue light, and full-color display is performed. It can be performed. Note that FIG. 2 and the like show an example in which the colored layer 545R that transmits red light, the colored layer 545G that transmits green light, and the colored layer 545B that transmits blue light are provided, but the present invention is not limited to this. is not limited to The visible light transmitted through the colored layer may be at least two colors of visible light different from each other, and may be appropriately selected from red, green, blue, cyan, magenta, yellow, or the like.

Therefore, even if the

layers

521, 522, 524, 525, the light-emitting layer 523Q_1, and the light-emitting layer 523Q_2 have the same structure (material, film thickness, and the like) in pixels of each color, colored layers can be provided as appropriate. , can display in full color. Therefore, in the display device according to one embodiment of the present invention, it is not necessary to separately manufacture a light-emitting device for each pixel; thus, manufacturing steps can be simplified and manufacturing costs can be reduced. However, the present invention is not limited to this, and one or more of 521, layer 522, layer 524, layer 525, light emitting layer 523Q_1, and light emitting layer 523Q_2 may have different structures depending on pixels.

A configuration in which a plurality of light-emitting units are connected in series via an intermediate layer 531, such as the light-emitting device 550W, is referred to herein as a tandem structure. On the other hand, a structure having one light-emitting unit between a pair of electrodes is called a single structure. In this specification and the like, it is called a tandem structure, but it is not limited to this, and for example, the tandem structure may be called a stack structure. Note that the tandem structure enables a light-emitting device capable of emitting light with high luminance. In addition, the tandem structure can reduce the current required to obtain the same luminance as compared with the single structure, so that the power consumption of the display device can be reduced and the reliability can be improved.

In FIG. 2A, the light-emitting unit 512Q_1, the intermediate layer 531, the light-emitting unit 512Q_2, and the layer 525 can be formed as island-shaped layers.

FIG. 2B is a modification of the display device 500 shown in FIG. 2A. A display device 500 shown in FIG. 2B is an example in which a layer 525 is provided in common among the light emitting devices similarly to the electrode 502 . At this time, layer 525 can be referred to as a common layer. By providing one or more common layers in a plurality of light-emitting devices in this manner, manufacturing steps can be simplified, and manufacturing costs can be reduced. Note that the common layer is not particularly limited. For example, one or more layers selected from a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer can be used as a common layer. For example, a hole injection layer and a hole transport layer may be provided in common for each light emitting device.

A display device 500 shown in FIG. 3A is an example in which a light-emitting device 550W has a configuration in which three light-emitting units are stacked. In FIG. 3A, the light-emitting device 550W has a light-emitting unit 512Q_3 laminated on the light-emitting unit 512Q_2 with an intermediate layer 531 interposed therebetween. The light-emitting unit 512Q_3 includes a layer 522, a light-emitting layer 523Q_3, a layer 524, and the like.

When applying a tandem structure to a light emitting device, the number of light emitting units is not particularly limited, and may be two or more.

FIG. 3B shows an example of stacking n light-emitting units (n is an integer of 2 or more).

By increasing the number of stacked light-emitting units in this way, the luminance obtained from the light-emitting device with the same amount of current can be increased according to the number of stacked layers. Further, by increasing the number of stacked light-emitting units, the current required to obtain the same luminance can be reduced, so the power consumption of the light-emitting device can be reduced according to the number of stacked layers.

In addition, in the display device 500, the light-emitting material of the light-emitting layer is not particularly limited. For example, in the display device 500 illustrated in FIG. 2A, the light-emitting layer 523Q_1 included in the light-emitting unit 512Q_1 can include a phosphorescent material, and the light-emitting layer 523Q_2 included in the light-emitting unit 512Q_2 can include a fluorescent material. Alternatively, the light-emitting layer 523Q_1 included in the light-emitting unit 512Q_1 can include a fluorescent material, and the light-emitting layer 523Q_2 included in the light-emitting unit 512Q_2 can include a phosphorescent material.

Note that the configuration of the light emitting unit is not limited to the above. For example, in the display device 500 shown in FIG. 2A, the light-emitting layer 523Q_1 included in the light-emitting unit 512Q_1 may include a TADF material, and the light-emitting layer 523Q_2 included in the light-emitting unit 512Q_2 may include either a fluorescent material or a phosphorescent material. good. By using different light-emitting materials in this way, for example, by combining a highly reliable light-emitting material and a light-emitting material with high light-emitting efficiency, the respective drawbacks are compensated for, and both reliability and light-emitting efficiency are improved. can be a device.

Note that the display device of one embodiment of the present invention may have a structure in which all the light-emitting layers are made of a fluorescent material, or a structure in which all the light-emitting layers are made of a phosphorescent material.

[Configuration example of display device]
Next, a display device of one embodiment of the present invention is described with reference to FIGS. 1A and 1B.

A display device of one embodiment of the present invention is a top emission type in which light is emitted in a direction opposite to a substrate over which a light-emitting device is formed, and light is emitted toward a substrate over which a light-emitting device is formed. Either a bottom emission type (bottom emission type) or a double emission type (dual emission type) in which light is emitted from both sides may be used.

FIG. 1A shows a top view (also referred to as a plan view) of the display device 100. FIG. The display device 100 has a display section in which a plurality of pixels 110 are arranged in a matrix, and a connection section 140 outside the display section. One pixel 110 is composed of three sub-pixels, sub-pixels 110a, 110b, and 110c.

There is no particular limitation on the arrangement of sub-pixels, and various methods can be applied. The arrangement of sub-pixels includes, for example, a stripe arrangement, an S-stripe arrangement, a matrix arrangement, a delta arrangement, a Bayer arrangement, and a pentile arrangement. A stripe arrangement is applied to the pixels 110 shown in FIG. 1A.

In addition, examples of top surface shapes of sub-pixels include triangles, quadrilaterals (including rectangles and squares), polygons such as pentagons, shapes with rounded corners of these polygons, ellipses, and circles. Here, the top surface shape of the sub-pixel corresponds to the top surface shape of the light emitting region of the light emitting device.

In this embodiment, the sub-pixels 110a, 110b, and 110c have light-emitting devices that emit white light, and

colored layers

125a, 125b, and 125c (hereinafter collectively referred to as colored layers 125 in some cases) provided thereon. ) shows an example in which each sub-pixel emits light of a different color. For example, the sub-pixels 110a, 110b, and 110c correspond to the sub-pixel having the colored layer 545R, the sub-pixel having the colored layer 545G, and the sub-pixel having the colored layer 545B shown in FIG. 2A and the like.

Although FIG. 1A shows an example in which the connecting portion 140 is positioned below the display portion in a top view (which can also be called a plan view), it is not particularly limited. The connecting portion 140 may be provided at least one of the upper side, the right side, the left side, and the lower side of the display portion when viewed from above, and may be provided so as to surround the four sides of the display portion. Moreover, the number of connection parts 140 may be singular or plural.

FIG. 1B shows cross-sectional views taken along dashed-dotted lines X1-X2, Y1-Y2, and Y3-Y4 in FIG. 1A.

As shown in FIG. 1B, the display device 100 includes light-emitting

devices

130a, 130b, and 130c (hereinafter collectively referred to as light-emitting devices 130) on a layer 101 including transistors. A protective layer 131 is provided to cover. Here, insulators 124 are provided on the side surfaces of the

light emitting devices

130a, 130b, and 130c.

Colored layers

125 a , 125 b , and 125 c are provided on the protective layer 131 . Furthermore, a substrate 120 is attached thereon with a resin layer 122 .

For the layer 101 including transistors, for example, a stacked structure in which a plurality of transistors are provided on a substrate and an insulating layer is provided to cover these transistors can be applied. A structural example of the layer 101 including a transistor will be described later in Embodiment 2. FIG.

The

light emitting devices

130a, 130b, and 130c preferably emit white (W) light. By providing

colored layers

125a, 125b, and 125c that transmit light of different colors on these layers, the sub-pixels 110a, 110b, and 110c that emit light of different colors can be formed.

A light-emitting device has an EL layer between a pair of electrodes. In this specification and the like, one of a pair of electrodes may be referred to as a pixel electrode and the other may be referred to as a common electrode.

Of the pair of electrodes that the light-emitting device has, one electrode functions as an anode and the other electrode functions as a cathode. A case where the pixel electrode functions as an anode and the common electrode functions as a cathode will be described below as an example.

The light emitting device 130a has a pixel electrode 111a on the layer 101 containing the transistor, a first layer 113 on the pixel electrode 111a, a second layer 114 on the first layer 113, and a second layer 114 on the second layer 114. and a common electrode 115 . Note that the first layer 113 and the second layer 114 can be collectively called an EL layer. Further, the light emitting device 130b differs from the light emitting device 130a in that pixel electrodes 111b are provided instead of the pixel electrodes 111a. Further, the light emitting device 130c differs from the light emitting device 130a in that pixel electrodes 111c are provided instead of the pixel electrodes 111a. Hereinafter, the

pixel electrodes

111a, 111b, and 111c may be collectively referred to as the pixel electrode 111 in some cases.

The first layer 113 has a first light emitting unit 192 on the pixel electrode 111a, an intermediate layer 191 on the first light emitting unit 192, and a second light emitting unit 194 on the intermediate layer 191. For example, the first light-emitting unit 192 includes a first hole-injection layer 181a on the pixel electrode 111a, a first hole-transport layer 182a on the first hole-injection layer 181a, and a first hole-injection layer 181a. It has a first light emitting layer 183a on the transport layer 182a and a first electron transport layer 184a on the first light emitting layer 183a. Further, for example, the second light-emitting unit 194 includes a second hole-transporting layer 182b on the intermediate layer 191, a second light-emitting layer 183b on the second hole-transporting layer 182b, and a second light-emitting layer and a second electron-transporting layer 184b on 183b.

The first light-emitting unit 192, the intermediate layer 191, and the second light-emitting unit 194 apply, for example, the same configurations as the light-emitting unit 512Q_1, the intermediate layer 531, and the light-emitting unit 512Q_2 shown in FIG. 2A, respectively. be able to. That is, the first light-emitting unit 192 can have

layers

521, 522, light-emitting layer 523Q_1, layer 524, and so on. Thus, the first hole-injecting layer 181a is the layer 521, the first hole-transporting layer 182a is the layer 522, the first light-emitting layer 183a is the light-emitting layer 523Q_1, and the first electron-transporting layer 184a is the layer 524. corresponds to Also, the second light-emitting unit 194 can have a layer 522, a light-emitting layer 523Q_2, a layer 524, and the like. Therefore, the second hole-transporting layer 182b corresponds to the layer 522, the second light-emitting layer 183b corresponds to the light-emitting layer 523Q_2, and the second electron-transporting layer 184b corresponds to the layer 524.

The second layer 114 is a layer common to the light emitting devices 130a to 130c. The second layer 114 has, for example, an electron injection layer. Alternatively, the second layer 114 may have a laminate of an electron transport layer and an electron injection layer.

The common electrode 115 is electrically connected to the conductive layer 123 provided on the connecting portion 140 . As a result, the same potential is supplied to the common electrodes 115 of the light emitting devices of each color.

A conductive film that transmits visible light and infrared light is used for the electrode on the light extraction side of the pixel electrode and the common electrode. A conductive film that reflects visible light and infrared light is preferably used for the electrode on the side from which light is not extracted.

As materials for forming the pair of electrodes (pixel electrode and common electrode) of the light-emitting device, metals, alloys, electrically conductive compounds, mixtures thereof, and the like can be used as appropriate. Specifically, indium tin oxide (also referred to as In—Sn oxide, ITO), In—Si—Sn oxide (also referred to as ITSO), indium zinc oxide (In—Zn oxide), In—W— Zn oxide, alloys containing aluminum (aluminum alloys) such as alloys of aluminum, magnesium, nickel and lanthanum (Al-Ni-La), alloys of silver and magnesium, and alloys of silver, palladium and copper ( silver-containing alloys such as Ag--Pd--Cu, also referred to as APC). In addition, aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn ), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y ), neodymium (Nd), and alloys containing appropriate combinations thereof can also be used. In addition, elements belonging to Group 1 or Group 2 of the periodic table of elements not exemplified above (e.g., lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), europium (Eu), ytterbium A rare earth metal such as (Yb), an alloy containing an appropriate combination thereof, graphene, or the like can be used. A pair of electrodes (a pixel electrode and a common electrode) of a light-emitting device may be formed by appropriately laminating the above metals, alloys, electrically conductive compounds, mixtures thereof, and the like.

A micro optical resonator (microcavity) structure is preferably applied to the light emitting device. Therefore, one of the pair of electrodes of the light-emitting device preferably has an electrode (semi-transmissive/semi-reflective electrode) that is transparent and reflective to visible light, and the other is an electrode that is reflective to visible light ( reflective electrode). Since the light-emitting device has a microcavity structure, the light emitted from the light-emitting layer can be resonated between both electrodes, and the light emitted from the light-emitting device can be enhanced.

Note that the semi-transmissive/semi-reflective electrode can have a laminated structure of a reflective electrode and an electrode having transparency to visible light (also referred to as a transparent electrode).

The light transmittance of the transparent electrode is set to 40% or more. For example, the light-emitting device preferably uses an electrode having a transmittance of 40% or more for visible light (light with a wavelength of 400 nm or more and less than 750 nm). The visible light reflectance of the semi-transmissive/semi-reflective electrode is 10% or more and 95% or less, preferably 30% or more and 80% or less. The visible light reflectance of the reflective electrode is 40% or more and 100% or less, preferably 70% or more and 100% or less. Moreover, the resistivity of these electrodes is preferably 1×10 ⁻² Ωcm or less. In addition, the transmittance or reflectance of near-infrared light (light having a wavelength of 750 nm or more and 1300 nm or less) of these electrodes preferably satisfies the above numerical range, similarly to the transmittance or reflectance of visible light.

In the first layer 113, the first light emitting unit 192 and the second light emitting unit 194 each have a light emitting layer. It is preferable to adopt a configuration in which white light emission is obtained by combining light from the light emitting layers of a plurality of light emitting units. The first light-emitting unit 192 and the second light-emitting unit 194 can each have one or more light-emitting layers.

A light-emitting layer is a layer containing a light-emitting substance. The emissive layer can have one or more emissive materials. As the light-emitting substance, a substance exhibiting emission colors such as blue, purple, violet, green, yellow-green, yellow, orange, and red is used as appropriate. Alternatively, a substance that emits near-infrared light can be used as the light-emitting substance.

Luminescent materials include fluorescent materials, phosphorescent materials, thermally activated delayed fluorescent materials, and quantum dot materials.

Examples of fluorescent materials include pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives. be done.

Examples of phosphorescent materials include organometallic complexes (especially iridium complexes) having a 4H-triazole skeleton, 1H-triazole skeleton, imidazole skeleton, pyrimidine skeleton, pyrazine skeleton, or pyridine skeleton, and phenylpyridine derivatives having an electron-withdrawing group. Organometallic complexes (especially iridium complexes), platinum complexes, rare earth metal complexes, etc., which are used as ligands, can be mentioned.

The light-emitting layer may contain one or more organic compounds (host material, assist material, etc.) in addition to the light-emitting substance (guest material). One or both of a hole-transporting material and an electron-transporting material can be used as the one or more organic compounds. Bipolar materials or TADF materials may also be used as one or more organic compounds.

The light-emitting layer preferably includes, for example, a phosphorescent material and a combination of a hole-transporting material and an electron-transporting material that easily form an exciplex. With such a structure, light emission using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from an exciplex to a light-emitting substance (phosphorescent material), can be efficiently obtained. By selecting a combination that forms an exciplex that emits light that overlaps with the wavelength of the absorption band on the lowest energy side of the light-emitting substance, energy transfer becomes smooth and light emission can be efficiently obtained. With this configuration, high efficiency, low-voltage driving, and long life of the light-emitting device can be realized at the same time.

The first layer 113 includes, as layers other than the light-emitting layer, a substance with a high hole-injection property, a substance with a high hole-transport property, a hole-blocking material, a substance with a high electron-transport property, a substance with a high electron-injection property, and an electron layer. A layer containing a block material, a bipolar substance (a substance with high electron-transport properties and hole-transport properties), or the like may be further included.

Both low-molecular-weight compounds and high-molecular-weight compounds can be used in the light-emitting device, and inorganic compounds may be included. Each of the layers constituting the light-emitting device can be formed by a vapor deposition method (including a vacuum vapor deposition method), a transfer method, a printing method, an inkjet method, a coating method, or the like.

For example, the first layer 113 may have one or more of a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer.

The second layer 114 may have one or more of a hole injection layer, a hole transport layer, a hole block layer, an electron block layer, an electron transport layer, and an electron injection layer. For example, if the

pixel electrodes

111a, 111b, 111c function as anodes and the common electrode 115 functions as a cathode, the second layer 114 preferably has an electron injection layer.

The hole-injecting layer is a layer that injects holes from the anode into the hole-transporting layer, and contains a material with high hole-injecting properties. Examples of highly hole-injecting materials include aromatic amine compounds and composite materials containing a hole-transporting material and an acceptor material (electron-accepting material).

In a light-emitting device, a hole-transporting layer is a layer that transports holes injected from the anode by the hole-injecting layer to the light-emitting layer. A hole-transporting layer is a layer containing a hole-transporting material. As the hole-transporting material, a substance having a hole mobility of 1×10 ⁻⁶ cm ² /Vs or more is preferable. Note that substances other than these can be used as long as they have a higher hole-transport property than electron-transport property. Examples of hole-transporting materials include π-electron-rich heteroaromatic compounds (e.g., carbazole derivatives, thiophene derivatives, furan derivatives, etc.), aromatic amines (compounds having an aromatic amine skeleton), and other highly hole-transporting materials. is preferred.

In a light-emitting device, an electron-transporting layer is a layer that transports electrons injected from the cathode by the electron-injecting layer to the light-emitting layer. The electron-transporting layer is a layer containing an electron-transporting material. As an electron-transporting material, a substance having an electron mobility of 1×10 ⁻⁶ cm ² /Vs or more is preferable. Note that substances other than these substances can be used as long as they have a higher electron-transport property than hole-transport property. Examples of electron-transporting materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, oxadiazole derivatives, triazole derivatives, imidazole derivatives, π-electrons including oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives with quinoline ligands, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other nitrogen-containing heteroaromatic compounds A material having a high electron-transport property such as a deficient heteroaromatic compound can be used.

The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer, and is a layer that contains a material with high electron injection properties. Alkali metals, alkaline earth metals, or compounds thereof can be used as materials with high electron injection properties. A composite material containing an electron-transporting material and a donor material (electron-donating material) can also be used as a material with high electron-injecting properties.

Examples of the electron injection layer include lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF ₂ ), 8-(quinolinolato)lithium (abbreviation: Liq), 2-(2 -pyridyl)phenoratritium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolatritium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenoratritium (abbreviation: LiPPP) , lithium oxide (LiO _x ), cesium carbonate, etc., alkali metals, alkaline earth metals, or compounds thereof.

Alternatively, an electron-transporting material may be used as the electron injection layer. For example, a compound having a lone pair of electrons and an electron-deficient heteroaromatic ring can be used as the electron-transporting material. Specifically, a compound having at least one of a pyridine ring, diazine ring (pyrimidine ring, pyrazine ring, pyridazine ring), and triazine ring can be used.

The lowest unoccupied molecular orbital (LUMO) of the organic compound having an unshared electron pair is preferably -3.6 eV or more and -2.3 eV or less. Generally, CV (cyclic voltammetry), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, etc. are used to determine the highest occupied molecular orbital (HOMO: Highest Occupied Molecular Orbital) level and LUMO level of an organic compound. can be estimated.

For example, 4,7-diphenyl-1,10-phenanthroline (abbreviation: BPhen), 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), diquinoxalino [2,3-a:2′,3′-c]phenazine (abbreviation: HATNA), 2,4,6-tris[3′-(pyridin-3-yl)biphenyl-3-yl]-1,3 , 5-triazine (abbreviation: TmPPPyTz) and the like can be used for organic compounds having a lone pair of electrons. Note that NBPhen has a higher glass transition point (Tg) than BPhen and has excellent heat resistance.

A material (also called a composite material) in which multiple types of substances are mixed can be used for the first layer 113 . Specifically, a composite material containing an alkali metal, an alkali metal compound, or an alkali metal complex and an electron-transporting material can be used for the first layer 113 . Note that the HOMO level of the electron-transporting material is more preferably −6.0 eV or higher.

Alternatively, a composite material of an acceptor material and a hole-transport material can be used for the first layer 113 . Specifically, a composite material of an acceptor material and a substance having a relatively deep HOMO level of −5.7 eV to −5.4 eV can be used for the first layer 113 . By using the composite material for the first layer 113, the reliability of the light-emitting device can be improved.

In this specification and the like, a light-emitting device using the composite material described above for the first layer 113 may be referred to as a Recombination-Site Tailoring Injection structure (ReSTI structure).

It is preferable to have a protective layer 131 on the

light emitting devices

130a, 130b, 130c. By providing the protective layer 131, the reliability of the light-emitting device can be improved.

The conductivity of the protective layer 131 does not matter. At least one of an insulating film, a semiconductor film, and a conductive film can be used as the protective layer 131 .

When the protective layer 131 includes an inorganic film or an inorganic insulating film, oxidation of the common electrode 115 can be prevented, and impurities (moisture, oxygen, or the like) can be prevented from entering the light-emitting

devices

130a, 130b, and 130c. can. This can suppress deterioration of the light-emitting device and improve the reliability of the display device.

For the protective layer 131, for example, inorganic insulating films such as an oxide insulating film, a nitride insulating film, an oxynitride insulating film, and a nitride oxide insulating film can be used. Examples of the oxide insulating film include a silicon oxide film, an aluminum oxide film, a gallium oxide film, a germanium oxide film, an yttrium oxide film, a zirconium oxide film, a lanthanum oxide film, a neodymium oxide film, a hafnium oxide film, a tantalum oxide film, and the like. . Examples of the nitride insulating film include a silicon nitride film and an aluminum nitride film. As the oxynitride insulating film, a silicon oxynitride film, an aluminum oxynitride film, or the like can be given. As the nitride oxide insulating film, a silicon nitride oxide film, an aluminum nitride oxide film, or the like can be given.

In this specification and the like, oxynitride refers to a material whose composition contains more oxygen than nitrogen, and nitride oxide refers to a material whose composition contains more nitrogen than oxygen. point to the material. For example, silicon oxynitride refers to a material whose composition contains more oxygen than nitrogen, and silicon nitride oxide refers to a material whose composition contains more nitrogen than oxygen. indicates

The protective layer 131 preferably has a nitride insulating film or a nitride oxide insulating film, and more preferably has a nitride insulating film.

In addition, the protective layer 131 includes In—Sn oxide (also referred to as ITO), In—Zn oxide, Ga—Zn oxide, Al—Zn oxide, or indium gallium zinc oxide (In—Ga—Zn oxide). Inorganic films containing materials such as IGZO can also be used. The inorganic film preferably has a high resistance, and specifically, preferably has a higher resistance than the common electrode 115 . The inorganic film may further contain nitrogen. For example, when a metal such as an alloy of silver and magnesium that is easily degraded by impurities (moisture, oxygen, etc.) is used for the common electrode 115 , In—Ga—Zn oxide or the like can be used as the protective layer 131 .

When the light emitted from the light-emitting device is taken out through the protective layer 131, the protective layer 131 preferably has high transparency to visible light. For example, ITO, IGZO, and aluminum oxide are preferable because they are inorganic materials with high transparency to visible light.

As the protective layer 131, for example, a stacked structure of an aluminum oxide film and a silicon nitride film over the aluminum oxide film, or a stacked structure of an aluminum oxide film and an IGZO film over the aluminum oxide film, or the like can be used. can be done. By using the stacked structure, impurities (such as water and oxygen) entering the EL layer can be suppressed.

Furthermore, the protective layer 131 may have an organic film. For example, protective layer 131 may have both an organic film and an inorganic film.

A colored layer 125 (a colored layer 125 a, a colored layer 125 b, and a colored layer 125 c ) is provided on the protective layer 131 . Colored layer 125a has a region that overlaps light emitting device 130a, colored layer 125b has a region that overlaps light emitting device 130b, and colored layer 125c has a region that overlaps light emitting device 130c. The

colored layers

125 a , 125 b , 125 c have at least regions overlapping the light emitting layers of the respective light emitting devices 130 .

The colored layer 125a, the colored layer 125b, and the colored layer 125c have a function of transmitting lights of different colors. For example, the colored layer 125a has a function of transmitting red light, the colored layer 125b has a function of transmitting green light, and the colored layer 125c has a function of transmitting blue light. Accordingly, the display device 100 can perform full-color display. Note that the colored layer 125a, the colored layer 125b, and the colored layer 125c may have a function of transmitting any one of cyan, magenta, and yellow light.

Here, adjacent colored layers 125 preferably have overlapping regions. Specifically, it is preferable to have a region where the adjacent colored layer 125 overlaps in a region that does not overlap with the light emitting device 130 . By overlapping the colored layers 125 that transmit light of different colors, the colored layers 125 can function as a light shielding layer in a region where the colored layers 125 overlap. Therefore, it is possible to suppress leakage of light emitted from the light emitting device 130 to adjacent sub-pixels. For example, light emitted from the light emitting device 130a overlapping the colored layer 125a can be prevented from entering the colored layer 125b. Therefore, the contrast of an image displayed on the display device can be increased, and a display device with high display quality can be realized.

Note that it is not necessary to have a region where adjacent colored layers 125 overlap. In this case, it is preferable to provide a light shielding layer in a region that does not overlap with the light emitting device 130 . The light shielding layer can be provided, for example, on the surface of the substrate 120 on the resin layer 122 side. Also, the colored layer 125 may be provided on the surface of the substrate 120 on the resin layer 122 side.

In addition, by forming the colored layer 125 on the protective layer 131, alignment between each light-emitting device 130 and each colored layer 125 is easier than in the case of forming the colored layer 125 on the substrate 120. A high-definition display device can be realized.

Each end of the

pixel electrodes

111a, 111b, and 111c is covered with an insulator 121. The insulator 121 can also be called a bank, partition, barrier, embankment, or the like. By providing such an insulator 121, the

pixel electrodes

111a, 111b, and 111c can be prevented from being in contact with the second layer 114, the common electrode 115, or the like, thereby suppressing a short circuit of the light emitting device . be able to.

Further, the insulator 121 has openings above the

pixel electrodes

111a, 111b, and 111c, respectively. , in contact with the first hole-injection layer 181a). That is, part of the insulator 121 is provided between the

pixel electrode

111a, 111b, or 111c and the first hole-injection layer 181a at or near the end of each of the

pixel electrodes

111a, 111b, and 111c. It is

The insulator 121 can have a single-layer structure or a laminated structure using one or both of an inorganic insulating film and an organic insulating film.

Examples of organic insulating materials that can be used for the insulator 121 include acrylic resins, epoxy resins, polyimide resins, polyamide resins, polyimideamide resins, polysiloxane resins, benzocyclobutene resins, and phenol resins. As an inorganic insulating film that can be used for the insulator 121, an inorganic insulating film that can be used for the protective layer 131 can be used.

When an inorganic insulating film is used as the insulator 121 covering the edge of the pixel electrode, impurities are less likely to enter the light-emitting device than when an organic insulating film is used, and the reliability of the light-emitting device can be improved. When an organic insulating film is used as the insulator 121 that covers the end portion of the pixel electrode, step coverage is high and the shape of the pixel electrode is less likely to affect it than when an inorganic insulating film is used. Therefore, short-circuiting of the light emitting device can be prevented. Specifically, when an organic insulating film is used as the insulator 121, the shape of the insulator 121 can be processed into a tapered shape or the like. Note that in this specification and the like, a tapered shape refers to a shape in which at least a part of the side surface of the structure is inclined with respect to the substrate surface. For example, it is preferable to have a region in which the angle formed by the inclined side surface and the substrate surface (also referred to as a taper angle) is less than 90°.

The insulator 124 is provided on the insulator 121 and in contact with at least part of the side surface of the light emitting device 130 . At this time, insulator 124 is preferably in contact with at least part of the side surface of first light emitting unit 192 , the side surface of intermediate layer 191 , and the side surface of second light emitting unit 194 . For example, as shown in FIG. 1B, the insulator 124 is formed on the sides of the first hole-injection layer 181a, the sides of the first hole-transport layer 182a, the sides of the first light-emitting layer 183a, and the first electron-transport layer. It can be in contact with the side surface of the layer 184a, the side surface of the intermediate layer 191, the side surface of the second hole-transport layer 182b, the side surface of the second light-emitting layer 183b, and the side surface of the second electron-transport layer 184b. By covering at least part of the side surface of the light-emitting device with the insulator 124 in this way, the second layer 114 is formed by the first light-emitting unit 192 , the intermediate layer 191 , and the second light-emitting unit 194 . can be suppressed from coming into contact with any side surface of As described above, the short circuit of the light emitting device 130 can be suppressed. Note that the insulator 124 can also be called a sidewall, a sidewall protective layer, a sidewall insulating film, or the like.

FIG. 1B shows an example in which the insulator 124 has a two-layer structure of an insulator 124a and an insulator 124b on the insulator 124a. Preferably, the side surface of the insulator 124a is in contact with at least part of the side surface of the light emitting device 130, and the lower surface of the insulator 124a is in contact with at least part of the insulator 121. FIG. Moreover, it is preferable that the side surface and the bottom surface of the insulator 124b are in contact with at least part of the insulator 124a.

Also, the thickness of the insulator 124b in the direction perpendicular to the substrate surface of the substrate 120 can be made thicker than the thickness of the insulator 124b in the direction parallel to the substrate surface of the substrate 120. Also, the shape of the upper end portion of the insulator 124b can be round. It is preferable that the upper end portion of the insulator 124b be rounded so that coverage with the second layer 114, the common electrode 115, and the protective layer 131 is improved.

For the

insulators

124a and 124b, inorganic insulating films such as oxide insulating films, nitride insulating films, oxynitride insulating films, and oxynitride insulating films can be used, for example. Examples of the oxide insulating film include a silicon oxide film, an aluminum oxide film, a gallium oxide film, a germanium oxide film, an yttrium oxide film, a zirconium oxide film, a lanthanum oxide film, a neodymium oxide film, a hafnium oxide film, a tantalum oxide film, and the like. . Examples of the nitride insulating film include a silicon nitride film and an aluminum nitride film. As the oxynitride insulating film, a silicon oxynitride film, an aluminum oxynitride film, or the like can be given. As the nitride oxide insulating film, a silicon nitride oxide film, an aluminum nitride oxide film, or the like can be given.

The

insulators

124a and 124b can be formed by various film formation methods such as sputtering, vapor deposition (including vacuum vapor deposition), CVD, and ALD. In particular, since the ALD method causes little film formation damage to the layers to be formed, the insulator 124a that is in direct contact with the first light-emitting unit 192, the intermediate layer 191, and the second light-emitting unit 194 is formed by the ALD method. preferably. At this time, it is preferable to form the insulator 124b by a sputtering method or the like because productivity can be increased.

For example, an aluminum oxide film formed by an ALD method can be used as the insulator 124a, and a silicon nitride film formed by a sputtering method can be used as the insulator 124b.

Further, one or both of the insulator 124a and the insulator 124b preferably have a function as a barrier insulating film against at least one of water and oxygen. Alternatively, one or both of the insulator 124a and the insulator 124b preferably have a function of suppressing diffusion of at least one of water and oxygen. Alternatively, one or both of the insulator 124a and the insulator 124b preferably have a function of capturing or fixing at least one of water and oxygen (also referred to as gettering).

Note that in this specification and the like, a barrier insulating film indicates an insulating film having barrier properties. In this specification and the like, the term "barrier property" refers to a function of suppressing diffusion of a corresponding substance (also referred to as low permeability). Alternatively, in this specification and the like, the term "barrier property" means the function of capturing or fixing (also referred to as gettering) a corresponding substance.

One or both of the insulator 124a and the insulator 124b have the above barrier insulating film function or gettering function, so that impurities (typically, water or oxygen) that can diffuse into each light-emitting element from the outside are prevented. It becomes a configuration that can suppress the intrusion of With such a structure, a highly reliable display device can be provided.

In this specification and the like, a device manufactured using a metal mask or FMM (fine metal mask, high-definition metal mask) may be referred to as a device with an MM (metal mask) structure. In this specification and the like, a device manufactured without using a metal mask or FMM may be referred to as a device with an MML (metal maskless) structure.

In this specification and the like, a light emitting device capable of emitting white light is sometimes called a white light emitting device. Note that a white light emitting device can be combined with a colored layer (for example, a color filter) to realize a full-color display device. In addition, a structure in which the light-emitting devices of each color (here, blue (B), green (G), and red (R)) are provided with separate light-emitting layers or painted separately is called a side-by-side (SBS) structure. Sometimes.

In addition, light-emitting devices can be broadly classified into single structures and tandem structures. A single-structure device preferably has one light-emitting unit between a pair of electrodes, and the light-emitting unit preferably includes one or more light-emitting layers. In order to obtain white light emission, it is sufficient to select light-emitting layers such that light emitted from each of the two or more light-emitting layers has a complementary color relationship. For example, by making the luminescent color of the first luminescent layer and the luminescent color of the second luminescent layer have a complementary color relationship, it is possible to obtain a configuration in which the entire light emitting device emits white light. The same applies to light-emitting devices having three or more light-emitting layers.

A tandem structure device preferably has two or more light-emitting units between a pair of electrodes, and each light-emitting unit preferably includes one or more light-emitting layers. In order to obtain white light emission, a structure in which white light emission is obtained by combining light from the light emitting layers of a plurality of light emitting units may be employed. Note that the structure for obtaining white light emission is the same as the structure of the single structure. In the tandem structure device, it is preferable to provide an intermediate layer such as a charge generation layer between the plurality of light emitting units.

In addition, when comparing the white light emitting device (single structure or tandem structure) and the light emitting device with the SBS structure, the manufacturing process of the white light emitting device is simpler than that of the light emitting device with the SBS structure. can be reduced or the manufacturing yield can be increased.

The display device of this embodiment can reduce the distance between the light emitting devices. Here, the distance between the light emitting devices can be, for example, the distance between the opposing side surfaces of the adjacent pixel electrodes 111 . Specifically, the distance between light emitting devices can be reduced to 8 μm or less, 6 μm or less, 4 μm or less, 3 μm or less, 2 μm or less, or even 1 μm or less. Furthermore, for example, by using an exposure apparatus for LSI, the gap can be narrowed to 500 nm or less, 200 nm or less, 100 nm or less, 90 nm or less, 70 nm or less, 50 nm or less, 30 nm or less, 20 nm or less, 15 nm or less, or even 10 nm. .

Although FIG. 1A illustrates an example in which the sub-pixels 110a, 110b, and 110c are arranged in stripes, the present invention is not limited to this. An example of a pixel array different from that shown in FIG. 1A will be described below with reference to FIGS. 4 to 6. FIG.

The S-stripe arrangement is applied to the pixels 110 shown in FIG. 4A. The pixel 110 shown in FIG. 4A is composed of three sub-pixels, sub-pixels 110a, 110b and 110c. Here, in the arrangement of sub-pixels of two rows and two columns, the sub-pixels 110b and 110c in the second column are arranged in the first and second rows, respectively, but the sub-pixel 110a in the first column is arranged in the first and second rows. , are arranged over the first and second rows. For example, sub-pixel 110a may be a blue sub-pixel, sub-pixel 110b may be a red sub-pixel, and sub-pixel 110c may be a green sub-pixel.

The pixel 110 shown in FIG. 4B includes a subpixel 110a having a substantially trapezoidal top surface shape with rounded corners, a subpixel 110b having a substantially triangular top surface shape with rounded corners, and a substantially square or substantially hexagonal top surface shape with rounded corners. and a sub-pixel 110c having Also, the sub-pixel 110a has a larger light emitting area than the sub-pixel 110b. Thus, the shape and size of each sub-pixel can be determined independently. For example, sub-pixels with more reliable light emitting devices can be smaller in size. For example, sub-pixel 110a may be a green sub-pixel, sub-pixel 110b may be a red sub-pixel, and sub-pixel 110c may be a blue sub-pixel.

A pentile array is applied to the

pixels

128a and 128b shown in FIG. 4C. FIG. 4C shows an example in which pixels 128a having sub-pixels 110a and 110b and pixels 128b having sub-pixels 110b and 110c are alternately arranged. For example, sub-pixel 110a may be a blue sub-pixel, sub-pixel 110b may be a green sub-pixel, and sub-pixel 110c may be a red sub-pixel.

A delta arrangement is applied to the

pixels

128a and 128b shown in FIGS. 4D and 4E. Pixel 128a has two sub-pixels (sub-pixels 110a and 110b) in the upper row (first row) and one sub-pixel (sub-pixel 110c) in the lower row (second row). Pixel 128b has one sub-pixel (sub-pixel 110c) in the upper row (first row) and two sub-pixels (sub-pixels 110a and 110b) in the lower row (second row).

FIG. 4D is an example in which each sub-pixel has a substantially square top surface shape with rounded corners, and FIG. 4E is an example in which each sub-pixel has a circular top surface shape.

In photolithography, the finer the pattern to be processed, the more difficult it is to ignore the effects of light diffraction. becomes difficult. Therefore, even if the photomask pattern is rectangular, a pattern with rounded corners is likely to be formed. Therefore, the top surface shape of the sub-pixel may be a polygonal shape with rounded corners, an elliptical shape, a circular shape, or the like.

Further, in the method for manufacturing a display device of one embodiment of the present invention, the EL layer is processed into an island shape using a resist mask. The resist film formed on the EL layer needs to be cured at a temperature lower than the heat resistance temperature of the EL layer. Therefore, depending on the heat resistance temperature of the EL layer material and the curing temperature of the resist material, curing of the resist film may be insufficient. A resist film that is insufficiently hardened may take a shape away from the desired shape during processing. As a result, the top surface shape of the EL layer may be a polygon with rounded corners, an ellipse, or a circle. For example, when a resist mask having a square top surface is formed, a resist mask having a circular top surface is formed, and the EL layer may have a circular top surface.

In order to obtain the desired shape of the upper surface of the EL layer, a technique (OPC (Optical Proximity Correction) technique) for correcting the mask pattern in advance so that the design pattern and the transfer pattern match. ) may be used. Specifically, in the OPC technique, a pattern for correction is added to a corner portion of a figure on a mask pattern.

Also, FIG. 1A shows a configuration in which three sub-pixels are provided, but the present invention is not limited to this. A configuration in which four or more sub-pixels are provided may be employed. The pixel 110 shown in FIG. 5A is composed of four sub-pixels, sub-pixels 110a, 110b, 110c and 110d. Subpixel 110d, like

subpixels

110a, 110b, and 110c, also has a light emitting device 130d that emits white light. As shown in FIG. 5B, the light emitting device 130d has a pixel electrode 111d, a first layer 113, a second layer 114, and a common electrode 115. As shown in FIG. However, unlike the sub-pixels 110a, 110b, and 110c, the sub-pixel 110d does not have a colored layer. With such a configuration, for example, the sub-pixels 110a, 110b, and 110c can be red, green, and blue sub-pixels, respectively, and the sub-pixel 110d can be a white sub-pixel.

FIG. 5A shows an example in which one pixel 110 is arranged in two rows and three columns. The pixel 110 has three sub-pixels (sub-pixels 110a, 110b, 110c) in the upper row (first row) and one sub-pixel (sub-pixel 110d) in the lower row (second row). have In other words, pixel 110 has sub-pixel 110a in the left column (first column), sub-pixel 110b in the middle column (second column), and sub-pixel 110b in the right column (third column). It has pixels 110c and sub-pixels 110d over these three columns.

A stripe arrangement is applied to the pixels 110 shown in FIGS. 6A to 6C. The pixel 110 shown in FIGS. 6A-6C is composed of four sub-pixels, sub-pixels 110a, 110b, 110c and 110d. The sub-pixels 110a, 110b, 110c, 110d have light emitting devices that emit different colors of light. For example, sub-pixels 110a, 110b, 110c, and 110d can be red, green, blue, and white sub-pixels, respectively.

6A is an example in which each sub-pixel has a rectangular top surface shape, FIG. 6B is an example in which each sub-pixel has a top surface shape connecting two semicircles and a rectangle, and FIG. This is an example where the sub-pixel has an elliptical top surface shape.

A matrix arrangement is applied to the pixels 110 shown in FIGS. 6D to 6F. The pixel 110 shown in FIGS. 6D-6F is composed of four sub-pixels, sub-pixels 110a, 110b, 110c and 110d. The sub-pixels 110a, 110b, 110c, 110d have light emitting devices that emit different colors of light. For example, sub-pixels 110a, 110b, 110c, and 110d can be red, green, blue, and white sub-pixels, respectively.

FIG. 6D is an example in which each sub-pixel has a square top surface shape, FIG. 6E is an example in which each sub-pixel has a substantially square top surface shape with rounded corners, and FIG. , which have a circular top shape.

A pixel 110 shown in FIG. 6G is composed of six sub-pixels: a sub-pixel 110a, a sub-pixel 110b, a sub-pixel 110c, a sub-pixel 110d1, a sub-pixel 110d2, and a sub-pixel 110d3. Subpixels 110d1, 110d2, and 110d3 in FIG. 6G are obtained by separating subpixel 110d shown in FIG. 5A parallel to

subpixels

110a, 110b, and 110c. Here, the sub-pixels 110d1, 110d2, and 110d3 may be electrically connected to the same transistor in the layer 101 including transistors.

With the configuration shown in FIG. 6G, the bottlenecks formed between the sub-pixels 110a, 110b, 110c, 110d1, 110d2, and 110d3 are formed across the display device 100 in the X direction or the Y direction. . This makes it easier for dust and the like to flow through the bottleneck in the cleaning process when manufacturing the display device 100, and prevents dust generated during the manufacturing process from entering the display device.

Next, modified examples of the cross-sectional shape of the display device 100 will be described with reference to FIGS. 7 to 9. FIG.

As shown in FIG. 7A, recesses may be formed in the upper portion of insulator 121 between adjacent light emitting devices 130 . For example, the first recess is formed in a region of the insulator 121 that does not overlap with the first layer 113 in some cases. At this time, the bottom surface of the insulator 124 may come into contact with the bottom surface of the first recess. Further, for example, a second recess may be formed in a region of the first recess that does not overlap with the insulator 124 . At this time, part of the second layer 114 may come into contact with the bottom surface of the second recess.

In addition, FIG. 1B shows an example in which the second layer 114 enters a region between adjacent insulators 124, etc., but as shown in FIG. good.

The voids 133 contain, for example, one or more selected from air, nitrogen, oxygen, carbon dioxide, and group 18 elements (typically helium, neon, argon, xenon, krypton, etc.).

Also, if the refractive index of the air gap 133 is lower than that of the second layer 114 , the light emitted from the light emitting device is reflected at the interface between the second layer 114 and the air gap 133 . This makes it possible to suppress the light emitted from the light emitting device from entering adjacent pixels (or sub-pixels). Therefore, it is possible to suppress color mixture of light from different pixels, so that the display quality of the display device can be improved.

In addition, although FIG. 1B shows an example in which the insulator 124 has the insulator 124a and the insulator 124b on the insulator 124a, the insulator 124 may have a single layer structure as shown in FIG. 8A. . The insulator 124 may be formed using a material that can be used for the insulator 124a or the insulator 124b.

In addition, although FIG. 1B shows an example in which the upper end of the insulator 124 approximately coincides with the upper surface of the second electron transport layer 184b, the present invention is not limited to this. For example, as shown in FIG. 8B, the upper end of one or both of the insulator 124a and the insulator 124b may protrude from the upper surface of the second electron transport layer 184b. With such a structure, the insulator 124 can cover the side surfaces of the first layer 113 up to the upper end, so short-circuiting of the light-emitting device 130 can be further suppressed.

In addition, FIG. 1B shows an example in which the

colored layers

125a, 125b, and 125c are in contact with the upper surface of the protective layer 131, but the present invention is not limited to this. For example, as shown in FIG. 9A, an insulating layer 126 having good flatness may be provided to cover the protective layer 131, and

colored layers

125a, 125b, and 125c may be provided on the insulating layer 126. FIG. Here, for the insulating layer 126, for example, an organic insulating material, an inorganic insulating material, or the like that can be used for the insulator 121 may be used. Furthermore, the resin layer 122 may be provided on the

colored layers

125a, 125b, and 125c, and the substrate 120 may be attached.

Further, as shown in FIG. 9B,

conductive layers

112a, 112b, and 112c (hereinafter collectively referred to as conductive layers) having a function of transmitting visible light are formed on the

pixel electrodes

111a, 111b, and 111c. 112) may be provided. At this time, the conductive layer 123 also has a laminated structure of the conductive layers 123a and 123b.

As the conductive layer 112, the above-described conductive film having transparency to visible light can be used. As the conductive layer 112, a conductive film that reflects visible light and is formed thin enough to transmit visible light can be used. Further, with the stacked structure of the conductive film and the conductive film that transmits visible light, conductivity and mechanical strength can be increased.

As shown in FIG. 9B, the conductive layer 112 is arranged between the pixel electrode 111 and the first hole injection layer 181a. A conductive layer 112 is located on the pixel electrode 111 .

Also, as shown in FIG. 9B, the conductive layer 112 provided in each light emitting device 130 preferably has a different thickness for each light emitting device. For example, when the colored layer 125a transmits red light, the colored layer 125b transmits green light, and the colored layer 125c transmits blue light, the conductive layer 112a is the thickest among the three conductive layers 112. However, the thickness of the conductive layer 112c may be minimized. Here, the distance between the upper surface of the pixel electrode 111 and the lower surface of the common electrode 115 in each light emitting device is the largest in the light emitting device 130 overlapping the colored layer 125a and the smallest in the light emitting device 130 overlapping the colored layer 125c. By changing the distance between the upper surface of the pixel electrode 111 and the lower surface of the common electrode 115 in each light emitting device, the optical distance (optical path length) in each light emitting element can be changed.

Of the three light-emitting devices, the light-emitting device 130 overlapping the colored layer 125a has the longest optical path length, so it emits light with the longest wavelength (for example, red light) intensified. On the other hand, the light-emitting device 130 overlapping the colored layer 125b has the shortest optical path length, and thus emits light in which the shortest wavelength light (for example, blue light) is intensified. The light-emitting device 130 overlapping the colored layer 125b emits light in which the intermediate wavelength light (for example, green light) is intensified.

With such a configuration, it is not necessary to separately prepare a light-emitting layer of the light-emitting device 130 for each sub-pixel of a different color, and color display with high color reproducibility can be performed using light-emitting devices having the same configuration. can be done.

[Example of manufacturing method of display device]
Next, an example of a method for manufacturing a display device is described with reference to FIGS. 10A to 10D show side by side a cross-sectional view along dashed line X1-X2, a cross-sectional view along Y1-Y2, and a cross-sectional view along Y3-Y4 in FIG. 1A. 11 to 13 are also the same as FIG.

The thin films (insulating films, semiconductor films, conductive films, etc.) that make up the display device are formed by sputtering, chemical vapor deposition (CVD), vacuum deposition, pulsed laser deposition (PLD). ) method, ALD method, or the like. CVD methods include a plasma enhanced CVD (PECVD) method, a thermal CVD method, and the like. Also, one of the thermal CVD methods is the metal organic CVD (MOCVD) method.

In addition, the thin films (insulating film, semiconductor film, conductive film, etc.) that make up the display device can be applied by spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife, slit coating, roll coating, It can be formed by methods such as curtain coating and knife coating.

In particular, vacuum processes such as vapor deposition and solution processes such as spin coating and inkjet can be used to fabricate light-emitting devices. Examples of vapor deposition methods include physical vapor deposition (PVD) such as sputtering, ion plating, ion beam vapor deposition, molecular beam vapor deposition, and vacuum vapor deposition, and chemical vapor deposition (CVD). In particular, the functional layers (hole injection layer, hole transport layer, light emitting layer, electron transport layer, electron injection layer, etc.) included in the EL layer may be formed by a vapor deposition method (vacuum vapor deposition method, etc.), a coating method (dip coating method, die coat method, bar coat method, spin coat method, spray coat method, etc.), printing method (inkjet method, screen (stencil printing) method, offset (lithographic printing) method, flexographic (letterpress printing) method, gravure method, or micro contact method, etc.).

In addition, when processing the thin film that constitutes the display device, a photolithography method or the like can be used. Alternatively, the thin film may be processed by a nanoimprint method, a sandblast method, a lift-off method, or the like. Alternatively, an island-shaped thin film may be directly formed by a film formation method using a shielding mask such as a metal mask.

As a photolithography method, there are typically the following two methods. One is a method of forming a resist mask on a thin film to be processed, processing the thin film by etching or the like, and removing the resist mask. The other is a method of forming a photosensitive thin film, then performing exposure and development to process the thin film into a desired shape.

In the photolithography method, the light used for exposure can be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture of these. In addition, ultraviolet rays, KrF laser light, ArF laser light, or the like can also be used. Moreover, you may expose by a liquid immersion exposure technique. As the light used for exposure, extreme ultraviolet (EUV: Extreme Ultra-violet) light or X-rays may be used. An electron beam can also be used instead of the light used for exposure. The use of extreme ultraviolet light, X-rays, or electron beams is preferable because extremely fine processing is possible. Note that a photomask may not be used when exposure is performed by scanning a beam such as an electron beam.

A dry etching method, a wet etching method, a sandblasting method, or the like can be used to etch the thin film.

First, as shown in FIG. 10A,

pixel electrodes

111a, 111b, and 111c and a conductive layer 123 are formed over a layer 101 including transistors. Each pixel electrode is provided in the display portion, and the conductive layer 123 is provided in the connection portion 140 .

Next, an insulator 121 covering the ends of the

pixel electrodes

111a, 111b, and 111c and the ends of the conductive layer 123 is formed.

Then, as shown in FIG. 10B, on each pixel electrode and on the insulator 121, a first hole-injection layer 181A, a first hole-transport layer 182A, a first light-emitting layer 183A, a first An electron-transporting layer 184A, an intermediate layer 191A, a second hole-transporting layer 182B, a second light-emitting layer 183B, and a second electron-transporting layer 184B are formed in this order, and a second layer is formed on the second electron-transporting layer 184B. A first sacrificial layer 118A is formed, and a second sacrificial layer 119A is formed on the first sacrificial layer 118A.

In FIG. 10B, in the cross-sectional view between Y1-Y2, the first hole-injection layer 181A, the first hole-transport layer 182A, the first light-emitting layer 183A, the first electron-transport layer 184A, the intermediate layer 191A, Example in which the second hole-transport layer 182B, the second light-emitting layer 183B, the second electron-transport layer 184B, the first sacrificial layer 118A, and the second sacrificial layer 119A are all provided over the conductive layer 123 is shown, but is not limited to this.

For example, the first hole-injection layer 181A, the first hole-transport layer 182A, the first light-emitting layer 183A, the first electron-transport layer 184A, the intermediate layer 191A, the second hole-transport layer 182B, the second The light-emitting layer 183B, the second electron-transporting layer 184B, and the first sacrificial layer 118A do not have to overlap with the conductive layer 123 . In addition, the first hole-injection layer 181A, the first hole-transport layer 182A, the first light-emitting layer 183A, the first electron-transport layer 184A, the intermediate layer 191A, the second hole-transport layer 182B, the second The ends of the light-emitting layer 183B and the second electron-transporting layer 184B on the side of the connecting portion 140 may be located inside the ends of the first sacrificial layer 118A and the second sacrificial layer 119A. For example, by using a mask (also referred to as an area mask, a rough metal mask, etc.) for defining a film formation area, the first hole-injection layer 181A, the first hole-transport layer 182A, and the first light-emitting layer are formed. 183A, a first electron-transporting layer 184A, an intermediate layer 191A, a second hole-transporting layer 182B, a second light-emitting layer 183B, and a second electron-transporting layer 184B; The area deposited with the sacrificial layer 119A can be changed. In one embodiment of the present invention, a light-emitting device is formed using a resist mask. By combining with an area mask as described above, a light-emitting device can be manufactured through a relatively simple process.

The materials that can be used as pixel electrodes are as described above. For example, a sputtering method or a vacuum deposition method can be used to form the pixel electrode.

The insulator 121 can have a single-layer structure or a laminated structure using one or both of an inorganic insulating film and an organic insulating film, as described above.

First hole injection layer 181A, first hole transport layer 182A, first light emitting layer 183A, first electron transport layer 184A, intermediate layer 191A, second hole transport layer 182B, second light emission Layer 183B and second electron-transporting layer 184B are respectively later formed into first hole-injecting layer 181a, first hole-transporting layer 182a, first light-emitting layer 183a, first electron-transporting layer 184a, These layers are to be the intermediate layer 191, the second hole-transporting layer 182b, the second light-emitting layer 183b, and the second electron-transporting layer 184b. Therefore, the first hole-injecting layer 181a, the first hole-transporting layer 182a, the first light-emitting layer 183a, the first electron-transporting layer 184a, the intermediate layer 191, and the second hole-transporting layer, respectively, are described above. Any structure applicable to the layer 182b, the second light-emitting layer 183b, and the second electron-transporting layer 184b can be applied.

First hole injection layer 181A, first hole transport layer 182A, first light emitting layer 183A, first electron transport layer 184A, intermediate layer 191A, second hole transport layer 182B, second light emission The layer 183B and the second electron-transporting layer 184B can each be formed by a vapor deposition method (including a vacuum vapor deposition method), a transfer method, a printing method, an inkjet method, a coating method, or the like. In addition, the first hole-injection layer 181A, the first hole-transport layer 182A, the first light-emitting layer 183A, the first electron-transport layer 184A, the intermediate layer 191A, the second hole-transport layer 182B, the second The light-emitting layer 183B and the second electron-transporting layer 184B may each be formed using a premixed material. In this specification and the like, a premix material is a composite material in which a plurality of materials are blended or mixed in advance.

In this embodiment mode, an example in which the sacrificial layer has a two-layer structure of a first sacrificial layer and a second sacrificial layer is shown. There may be. The sacrificial layer includes a first hole-injection layer 181A, a first hole-transport layer 182A, a first light-emitting layer 183A, a first electron-transport layer 184A, an intermediate layer 191A, and a second hole-transport layer 182B. , the second light-emitting layer 183B, and the second electron-transporting layer 184B, a film having high resistance to processing conditions, specifically, a film having a high etching selectivity is used.

For example, a sputtering method, an ALD method (thermal ALD method, PEALD method), or a vacuum deposition method can be used to form the sacrificial layer. Note that a formation method that causes less damage to the EL layer is preferable, and the sacrificial layer is preferably formed by an ALD method or a vacuum evaporation method rather than a sputtering method.

A film that can be removed by wet etching is preferably used for the sacrificial layer. By using the wet etching method, the first hole-injection layer 181A, the first hole-transport layer 182A, the first light-emitting layer 183A, the first light-emitting layer 183A, the first hole-injection layer 182A, the first hole-transport layer 183A, the first hole-transport layer 183A, the first hole-transport layer 183A, and the first hole-transport layer 183A can be formed more easily during processing of the sacrificial layer than when the dry etching method is used. Damage to the electron-transporting layer 184A, the intermediate layer 191A, the second hole-transporting layer 182B, the second light-emitting layer 183B, and the second electron-transporting layer 184B can be reduced.

In the process of processing various sacrificial layers in the manufacturing method of the display device of this embodiment, various functional layers constituting the light-emitting device (hole injection layer, hole transport layer, light emitting layer, active layer, electron transport layer, etc.) ) is difficult to process, and it is desirable that various sacrificial layers are difficult to process in the process of processing the functional layer. It is desirable to select the material of the sacrificial layer, the processing method, and the processing method of the functional layer in consideration of these.

As the sacrificial layer, for example, an inorganic film such as a metal film, an alloy film, a metal oxide film, a semiconductor film, or an inorganic insulating film can be used.

The sacrificial layer includes metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or the metal materials. An alloy material containing

In addition, a metal oxide such as In--Ga--Zn oxide can be used for the sacrificial layer. As the sacrificial layer, for example, an In--Ga--Zn oxide film can be formed using a sputtering method. Furthermore, indium oxide, In-Zn oxide, In-Sn oxide, indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide ( In--Ti--Zn oxide), indium gallium tin-zinc oxide (In--Ga--Sn--Zn oxide), or the like can be used. Alternatively, indium tin oxide containing silicon or the like can be used.

In place of gallium, element M (M is aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten , or one or more selected from magnesium) may be used.

Various inorganic insulating films that can be used for the protective layer 131 can be used as the sacrificial layer. In particular, an oxide insulating film is preferable because it has higher adhesion to the EL layer than a nitride insulating film. For example, inorganic insulating materials such as aluminum oxide, hafnium oxide, and silicon oxide can be used for the sacrificial layer. As the sacrificial layer, for example, an aluminum oxide film can be formed using the ALD method. Use of the ALD method is preferable because damage to the base (especially the EL layer or the like) can be reduced.

For example, a lamination structure of an In—Ga—Zn oxide film formed by a sputtering method and an aluminum oxide film formed on the In—Ga—Zn oxide film by an ALD method is applied as the sacrificial layer. can do. Alternatively, a lamination structure of an aluminum oxide film formed by an ALD method and an In--Ga--Zn oxide film formed over the aluminum oxide film by a sputtering method can be used as the sacrificial layer. Further, as the sacrificial layer, a single-layer structure of an aluminum oxide film formed by an ALD method can be applied.

Next, as shown in FIG. 10C, a resist mask 190 is formed on the second sacrificial layer 119A. A resist mask can be formed by applying a photosensitive resin (photoresist), followed by exposure and development. The resist mask 190 is provided at positions overlapping with the

pixel electrodes

111a, 111b, and 111c. The resist mask 190 preferably does not overlap with the conductive layer 123 .

Then, as shown in FIG. 10D, a resist mask 190 is used to partially remove the second sacrificial layer 119A. As a result, a region of the second sacrificial layer 119A that does not overlap with the resist mask 190 can be removed. Therefore, the second sacrificial layer 119 remains at positions overlapping with the

pixel electrodes

111a, 111b, and 111c. After that, the resist mask 190 is removed.

Next, as shown in FIG. 11A, the second sacrificial layer 119 is used to partially remove the first sacrificial layer 118A. As a result, the region of the first sacrificial layer 118A that does not overlap with the second sacrificial layer 119 can be removed. Therefore, a layered structure of the first sacrificial layer 118 and the second sacrificial layer 119 remains at positions overlapping with the

pixel electrodes

111a, 111b, and 111c.

Next, as shown in FIG. 11B, using a first sacrificial layer 118 and a second sacrificial layer 119, a portion of the first hole injection layer 181A and a portion of the first hole transport layer 182A are separated. , part of the first light-emitting layer 183A, part of the first electron-transporting layer 184A, part of the intermediate layer 191A, part of the second hole-transporting layer 182B, part of the second light-emitting layer 183B. , and a portion of the second electron transport layer 184B. Thus, the first hole-injection layer 181A, the first hole-transport layer 182A, the first light-emitting layer 183A, the first electron-transport layer 184A, the intermediate layer 191A, the second hole-transport layer 182B, the second Regions of the second light-emitting layer 183B and the second electron-transporting layer 184B that do not overlap with the first sacrificial layer 118 and the second sacrificial layer 119 can be removed. Therefore, the conductive layer 123 is exposed. Then, over the

pixel electrodes

111a, 111b, and 111c, a first hole-injection layer 181a, a first hole-transport layer 182a, a first light-emitting layer 183a, a first electron-transport layer 184a, an intermediate layer 191, a second A stacked structure of two hole-transporting layers 182b, a second light-emitting layer 183b, a second electron-transporting layer 184b, a first sacrificial layer 118, and a second sacrificial layer 119 remains.

Note that the stacked structure of the first hole-injection layer 181a, the first hole-transport layer 182a, the first light-emitting layer 183a, and the first electron-transport layer 184a is sometimes referred to as a first light-emitting unit 192. be. A stacked structure of the second hole-transport layer 182b, the second light-emitting layer 183b, and the second electron-transport layer 184b is sometimes called a second light-emitting unit 194. Also, the stacked structure of the first light-emitting unit 192 , the intermediate layer 191 , and the second light-emitting unit 194 is sometimes called the first layer 113 .

The first sacrificial layer 118A and the second sacrificial layer 119A can be processed by wet etching or dry etching, respectively. The first sacrificial layer 118A and the second sacrificial layer 119A are preferably processed by anisotropic etching.

By using the wet etching method, the first hole-injection layer 181A, the first hole-transport layer 182A, the first light-emitting layer 183A, the first light-emitting layer 183A, the first hole-injection layer 182A, the first hole-transport layer 183A, the first hole-transport layer 183A, the first hole-transport layer 183A, and the first hole-transport layer 183A can be formed more easily during processing of the sacrificial layer than when the dry etching method is used. Damage to the electron-transporting layer 184A, the intermediate layer 191A, the second hole-transporting layer 182B, the second light-emitting layer 183B, and the second electron-transporting layer 184B can be reduced. When a wet etching method is used, for example, a developer, a tetramethylammonium hydroxide (TMAH) aqueous solution, dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a chemical solution using a mixed liquid thereof can be used. preferable.

In the case of using a dry etching method, the first hole-injection layer 181A, the first hole-transport layer 182A, the first light-emitting layer 183A, the first light-emitting layer 183A, and the first hole-injection layer 181A are formed by not using a gas containing oxygen as an etching gas. The deterioration of the electron-transporting layer 184A, the intermediate layer 191A, the second hole-transporting layer 182B, the second light-emitting layer 183B, and the second electron-transporting layer 184B can be suppressed. When a dry etching method is used, a gas containing a noble gas (also referred to as a noble gas) such as CF ₄ , C ₄ F ₈ , SF ₆ , CHF ₃ , Cl ₂ , H ₂ O, BCl ₃ , or He is used for etching. Gases are preferred.

Since the sacrificial layer has a laminated structure, some layers are processed using the resist mask 190, and after removing the resist mask 190, the partial layers are used as a hard mask to process the remaining layers. be able to.

For example, after processing the second sacrificial layer 119A using the resist mask 190, the resist mask 190 is removed by ashing using oxygen plasma or the like. At this time, the first sacrificial layer 118A is located on the outermost surface, and the first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, the first electron transport layer 184A, the intermediate layer Layer 191A, second hole-transporting layer 182B, second light-emitting layer 183B, and second electron-transporting layer 184B are not exposed. Therefore, in the step of removing the resist mask 190, the first hole-injection layer 181A, the first hole-transport layer 182A, the first light-emitting layer 183A, the first electron-transport layer 184A, the intermediate layer 191A, the second Damage to the hole-transport layer 182B, the second light-emitting layer 183B, and the second electron-transport layer 184B can be suppressed. Then, using the second sacrificial layer 119 as a hard mask, the first sacrificial layer 118A can be processed. 1 hole injection layer 181A, first hole transport layer 182A, first light emitting layer 183A, first electron transport layer 184A, intermediate layer 191A, second hole transport layer 182B, second light emitting layer 183B, and the second electron-transporting layer 184B can be processed.

First hole injection layer 181A, first hole transport layer 182A, first light emitting layer 183A, first electron transport layer 184A, intermediate layer 191A, second hole transport layer 182B, second light emission The layer 183B and the second electron-transporting layer 184B are preferably processed by anisotropic etching. Anisotropic dry etching is particularly preferred. As an etching gas, a gas containing nitrogen, a gas containing hydrogen, a gas containing noble gas, a gas containing nitrogen and argon, a gas containing nitrogen and hydrogen, or the like is preferably used. By not using a gas containing oxygen as the etching gas, the first hole injection layer 181A, the first hole transport layer 182A, the first light emitting layer 183A, the first electron transport layer 184A, the intermediate layer 191A, Deterioration of the second hole-transport layer 182B, the second light-emitting layer 183B, and the second electron-transport layer 184B can be suppressed.

Here, part of the upper portion of the insulator 121 that does not overlap with the resist mask 190 may be removed by the above etching treatment. In this case, as shown in FIG. 7A, the insulator 121 is formed with a first concave portion on the top. The first concave portion is formed in a region that does not overlap with the first layer 113 .

Next, as shown in FIG. 11C, an insulating film 124A is formed to cover the first layer 113, the first sacrificial layer 118, and the second sacrificial layer 119. Then, as shown in FIG. Further, an insulating film 124B is formed on the insulating film 124A. A material that can be used for the insulator 124a and the insulator 124 may be used for the insulating film 124A and the insulating film 124B.

Methods for forming the insulating film 124A and the insulating film 124B include a vacuum deposition method, a sputtering method, a CVD method, an ALD method, and the like. The insulating film 124A is preferably formed by a method that causes less damage to the first layer 113 . In addition, the insulating

films

124A and 124B are formed at a temperature lower than the heat-resistant temperature of the first layer 113 . For example, as the insulating film 124A, an aluminum oxide film can be formed using the ALD method. The use of the ALD method is preferable because a film with high coverage can be formed. Alternatively, for example, a silicon oxynitride film or a silicon nitride film can be formed as the insulating film 124B by a PECVD method or a sputtering method.

Next, as shown in FIG. 12A, the insulator 124b is formed by etching the insulating film 124B. The insulating film 124B is preferably processed by anisotropic etching. Anisotropic dry etching is particularly preferred. For example, gases containing noble gases such as CF ₄ , C ₄ F ₈ , SF ₆ , CHF ₃ , Cl ₂ , H ₂ O, BCl ₃ , or He can be used as the etching gas.

Next, as shown in FIG. 12B, using the insulator 124b as a hard mask, the insulating film 124A is etched to form an insulator 124a. The insulating film 124A is preferably processed using a wet etching method. By using the wet etching method, damage to the second sacrificial layer 119 and the like can be reduced when the insulator 124a is processed, compared to the case of using the dry etching method. When a wet etching method is used, for example, a developer, a tetramethylammonium hydroxide aqueous solution (TMAH), dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a chemical solution using a mixed liquid thereof can be used. preferable.

Thus, the insulator 124 in which the insulator 124b is laminated on the insulator 124a can be formed. The insulator 124 has a side surface in contact with the first layer 113 and a bottom surface in contact with the insulator 121 . This can prevent the light-emitting device 130 from short-circuiting due to contact between the second layer 114 or the common electrode 115 to be formed later and the side surface of the pixel electrode 111 or the side surface of the first layer 113 . In addition, damage to the first layer 113 in subsequent steps can be suppressed.

Here, part of the upper portion of the insulator 121 that does not overlap with the insulator 124 may be removed by the etching treatment. In this case, as shown in FIG. 7A, the insulator 121 is formed with a second recess on the top. The second recess is formed in a region of the first recess that does not overlap the insulator 124 .

Next, as shown in FIG. 12C, the second sacrificial layer 119 is removed. Further, as shown in FIG. 13A, the first sacrificial layer 118 is removed. As a result, the second electron transport layer 184b is exposed on the pixel electrode 111, and the conductive layer 123 is exposed on the connection portion 140. Next, as shown in FIG.

For the sacrificial layer removing process, the same method as the sacrificial layer processing process can be used. In particular, by using the wet etching method, damage to the first layer 113, the conductive layer 123, and the insulator 124 can be reduced in removing the sacrificial layer compared to the case of using the dry etching method. can.

Next, as shown in FIG. 13B, a second layer 114 is formed so as to cover the first layer 113, the conductive layer 123, the insulator 124, and the insulator 121, and the second layer 114 and the insulating layer are formed. A common electrode 115 is formed over the body 121 and the conductive layer 123 .

The materials that can be used for the second layer 114 are as described above. Each of the layers that constitute the second layer 114 can be formed by a vapor deposition method (including a vacuum vapor deposition method), a transfer method, a printing method, an inkjet method, a coating method, or the like. Also, the layers constituting the second layer 114 may be formed using a premix material. Note that the second layer 114 may be omitted if unnecessary.

The materials that can be used as the common electrode 115 are as described above. For forming the common electrode 115, for example, a sputtering method or a vacuum deposition method can be used.

Then, as shown in FIG. 13B, a protective layer 131 is formed on the common electrode 115 .

The materials that can be used for the protective layer 131 are as described above. Methods for forming the protective layer 131 include a vacuum deposition method, a sputtering method, a CVD method, an ALD method, and the like. The protective layer 131 may have a single layer structure or a laminated structure. For example, the protective layer 131 may have a laminated structure of two layers formed using different film formation methods.

Subsequently,

colored layers

125a, 125b, and 125c are formed on the protective layer 131 so as to have regions overlapping with the

pixel electrodes

111a, 111b, and 111c. The

colored layers

125a, 125b, and 125c can be formed at desired positions by an inkjet method, an etching method using a photolithography method, or the like. Specifically, a different colored layer 125 (colored layer 125a, colored layer 125b, or colored layer 125c) can be formed for each pixel.

Then, by bonding the substrate 120 onto the protective layer 131 using the resin layer 122, the display device 100 shown in FIG. 1B can be manufactured.

As described above, in the manufacturing method of the display device of this embodiment mode, the island-shaped EL layer is not formed by the pattern of the metal mask, but is formed by forming the EL layer over one surface and then processing the EL layer. Therefore, the island-shaped EL layer can be formed with a uniform thickness. In addition, it is possible to realize a high-definition display device or a display device with a high aperture ratio, which has been difficult to achieve.

A display device of one embodiment of the present invention includes a tandem light-emitting device. Then, side surfaces of the pixel electrode, the light emitting layer, the carrier transport layer, the carrier injection layer, and the intermediate layer of the light emitting device are covered with sidewall-shaped insulators and bank-shaped insulators. With such a configuration, contact between the common electrode and the side surfaces of the pixel electrode, the light emitting layer, the carrier transport layer, the carrier injection layer, and the intermediate layer is suppressed. can be suppressed.

This embodiment can be appropriately combined with other embodiments. Further, in this specification, when a plurality of configuration examples are shown in one embodiment, the configuration examples can be combined as appropriate.

(Embodiment 2)
In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS.

The display device of this embodiment can be a high-resolution display device or a large-sized display device. Therefore, the display device of the present embodiment includes a relatively large screen such as a television device, a desktop or notebook personal computer, a computer monitor, a digital signage, a large game machine such as a pachinko machine, or the like. In addition to electronic devices, it can be used for display portions of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound reproducing devices.

[Display device 100A]
FIG. 14 shows a perspective view of the display device 100A, and FIG. 15A shows a cross-sectional view of the display device 100A.

The display device 100A has a configuration in which a substrate 152 and a substrate 151 are bonded together. In FIG. 14, the substrate 152 is clearly indicated by dashed lines.

The display device 100A has a display section 162, a circuit 164, wiring 165, and the like. FIG. 14 shows an example in which an IC 173 and an FPC 172 are mounted on the display device 100A. Therefore, the configuration shown in FIG. 14 can also be said to be a display module including the display device 100A, an IC (integrated circuit), and an FPC.

A scanning line driving circuit, for example, can be used as the circuit 164 .

The wiring 165 has a function of supplying signals and power to the display section 162 and the circuit 164 . The signal and power are input to the wiring 165 from the outside through the FPC 172 or input to the wiring 165 from the IC 173 .

FIG. 14 shows an example in which an IC 173 is provided on a substrate 151 by a COG (Chip On Glass) method, a COF (Chip On Film) method, or the like. For the IC 173, for example, an IC having a scanning line driver circuit or a signal line driver circuit can be applied. Note that the display device 100A and the display module may be configured without an IC. Also, the IC may be mounted on the FPC by the COF method or the like.

FIG. 15A shows an example of a cross-section of the display device 100A when a portion of the region including the FPC 172, a portion of the circuit 164, a portion of the display section 162, and a portion of the region including the end are cut. show.

A display device 100A shown in FIG. 15A includes a transistor 201, a transistor 205, a light-emitting device 130a, a light-emitting device 130b, a colored layer 125a, a colored layer 125b, and the like between a substrate 151 and a substrate 152. Light emitting device 130a and light emitting device 130b emit white light. The colored layer 125a and the colored layer 125b have a function of transmitting lights of different colors. Although two types of colored layers are shown in FIG. 15A, more types of colored layers are provided in the display device 100A.

Here, when the pixels of the display device have three types of sub-pixels having the colored layers 125 that transmit light of different colors, the three sub-pixels are R, G, and B sub-pixels, Examples include sub-pixels of three colors of yellow (Y), cyan (C), and magenta (M). When the four sub-pixels are provided, the four sub-pixels include R, G, B, and white (W) sub-pixels, and R, G, B, and Y four-color sub-pixels. be done.

The protective layer 131 and the substrate 152 are adhered via the adhesive layer 142 . A solid sealing structure, a hollow sealing structure, or the like can be applied to sealing the light-emitting device. In FIG. 15A, the space between

substrates

152 and 151 is filled with an adhesive layer 142 to apply a solid sealing structure. Alternatively, the space may be filled with an inert gas (such as nitrogen or argon) to apply a hollow sealing structure. At this time, the adhesive layer 142 may be provided so as not to overlap the light emitting device. Further, the space may be filled with a resin different from the adhesive layer 142 provided in a frame shape.

The light emitting device 130a has a layered structure similar to that of the light emitting device 130a shown in FIG. 1B, and the light emitting device 130b has a layered structure similar to that of the light emitting device 130b shown in FIG. 1B. Embodiment 1 can be referred to for details of the light-emitting device. An insulator 124 is formed in contact with the side surface of the light emitting device 130a and the side surface of the light emitting device 130b. A protective layer 131 is formed to cover the

light emitting devices

130a and 130b, the insulator 124, and the insulator 121. FIG.

The pixel electrode 111 a is connected to the conductive layer 222 b of the transistor 205 through an opening provided in the insulating layer 214 . Similarly, the pixel electrode 111b is electrically connected to one of the source electrode and the drain electrode of the transistor 205 through an opening provided in the insulating layer 214 .

A region including the ends of the

pixel electrodes

111 a and 111 b is covered with an insulator 121 . The

pixel electrodes

111a and 111b contain a material that reflects visible light, and the common electrode 115 contains a material that transmits visible light.

The light emitted by the light emitting device is emitted to the substrate 152 side. Therefore, it is preferable that the substrate 152 be made of a material that is highly transparent to visible light.

A layered structure from the substrate 151 to the insulating layer 214 corresponds to the layer 101 including the transistor in the first embodiment.

Both the transistor 201 and the transistor 205 are formed over the substrate 151 . These transistors can be made with the same material and the same process.

An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided on the substrate 151 in this order. Part of the insulating layer 211 functions as a gate insulating layer of each transistor. Part of the insulating layer 213 functions as a gate insulating layer of each transistor. An insulating layer 215 is provided over the transistor. An insulating layer 214 is provided over the transistor and functions as a planarization layer. Note that the number of gate insulating layers and the number of insulating layers covering a transistor are not limited, and each may have a single layer or two or more layers.

It is preferable to use a material in which impurities such as water and hydrogen are difficult to diffuse for at least one insulating layer covering the transistor. This allows the insulating layer to function as a barrier insulating film. With such a structure, diffusion of impurities from the outside into the transistor can be effectively suppressed, and the reliability of the display device can be improved.

Inorganic insulating films are preferably used for the insulating layer 211, the insulating layer 213, and the insulating layer 215, respectively. As the inorganic insulating film, for example, a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, an aluminum nitride film, or the like can be used. Alternatively, a hafnium oxide film, an yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, a neodymium oxide film, or the like may be used. Further, two or more of the insulating films described above may be laminated and used.

An organic insulating film is suitable for the insulating layer 214 that functions as a planarizing layer. Examples of materials that can be used for the organic insulating film include acrylic resins, polyimide resins, epoxy resins, polyamide resins, polyimideamide resins, siloxane resins, benzocyclobutene-based resins, phenolic resins, precursors of these resins, and the like. .

Here, organic insulating films often have lower barrier properties than inorganic insulating films. Therefore, the organic insulating film preferably has openings near the ends of the display device 100A. As a result, it is possible to prevent impurities from entering through the organic insulating film from the end portion of the display device 100A. Alternatively, the organic insulating film may be formed so that the edges of the organic insulating film are located inside the edges of the display device 100A so that the organic insulating film is not exposed at the edges of the display device 100A.

An opening is formed in the insulating layer 214 in a region 228 shown in FIG. 15A. As a result, even when an organic insulating film is used for the insulating layer 214 , it is possible to prevent impurities from entering the display section 162 from the outside through the insulating layer 214 . Therefore, the reliability of the display device 100A can be improved.

In the

transistors

201 and 205, a conductive layer 221 functioning as a gate, an insulating layer 211 functioning as a gate insulating layer,

conductive layers

222a and 222b functioning as sources and drains, a semiconductor layer 231, and a gate insulating layer. It has an insulating layer 213 and a conductive layer 223 functioning as a gate. Here, the same hatching pattern is applied to a plurality of layers obtained by processing the same conductive film. The insulating layer 211 is located between the conductive layer 221 and the semiconductor layer 231 . The insulating layer 213 is located between the conductive layer 223 and the semiconductor layer 231 .

There is no particular limitation on the structure of the transistor included in the display device of this embodiment. For example, a planar transistor, a staggered transistor, an inverted staggered transistor, or the like can be used. Further, the transistor structure may be either a top-gate type or a bottom-gate type. Alternatively, gates may be provided above and below a semiconductor layer in which a channel is formed.

A structure in which a semiconductor layer in which a channel is formed is sandwiched between two gates is applied to the

transistors

201 and 205 . A transistor may be driven by connecting two gates and applying the same signal to them. Alternatively, the threshold voltage of the transistor may be controlled by applying a potential for controlling the threshold voltage to one of the two gates and applying a potential for driving to the other.

Crystallinity of a semiconductor material used for a transistor is not particularly limited, either an amorphous semiconductor or a semiconductor having crystallinity (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor partially including a crystal region). may be used. It is preferable to use a crystalline semiconductor because deterioration of transistor characteristics can be suppressed.

A semiconductor layer of a transistor preferably includes a metal oxide (also referred to as an oxide semiconductor). In other words, the display device of this embodiment preferably uses a transistor including a metal oxide for a channel formation region (hereinafter referred to as an OS transistor). Alternatively, the semiconductor layer of the transistor may comprise silicon. Examples of silicon include amorphous silicon and crystalline silicon (low-temperature polysilicon, monocrystalline silicon, etc.).

The semiconductor layer includes, for example, indium and M (M is gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, one or more selected from hafnium, tantalum, tungsten, and magnesium) and zinc. In particular, M is preferably one or more selected from aluminum, gallium, yttrium, and tin.

In particular, it is preferable to use an oxide (also referred to as IGZO) containing indium (In), gallium (Ga), and zinc (Zn) as the semiconductor layer.

When the semiconductor layer is an In-M-Zn oxide, the atomic ratio of In in the In-M-Zn oxide is preferably equal to or higher than the atomic ratio of M. As the atomic number ratio of the metal elements of such In-M-Zn oxide, In:M:Zn=1:1:1 or a composition in the vicinity thereof, In:M:Zn=1:1:1.2 or In:M:Zn=2:1:3 or its neighboring composition In:M:Zn=3:1:2 or its neighboring composition In:M:Zn=4:2:3 or a composition in the vicinity thereof, In:M:Zn=4:2:4.1 or a composition in the vicinity thereof, In:M:Zn=5:1:3 or a composition in the vicinity thereof, In:M:Zn=5: 1:6 or thereabouts, In:M:Zn=5:1:7 or thereabouts, In:M:Zn=5:1:8 or thereabouts, In:M:Zn=6 :1:6 or a composition in the vicinity thereof, In:M:Zn=5:2:5 or a composition in the vicinity thereof, and the like. It should be noted that the neighboring composition includes a range of ±30% of the desired atomic number ratio.

For example, when the atomic ratio of In:Ga:Zn=4:2:3 or a composition in the vicinity thereof is described, when the atomic ratio of In is 4, the atomic ratio of Ga is 1 or more and 3 or less. , and Zn having an atomic ratio of 2 or more and 4 or less. Further, when the atomic ratio of In:Ga:Zn=5:1:6 or a composition in the vicinity thereof is described, when the atomic ratio of In is 5, the atomic ratio of Ga is greater than 0.1. 2 or less, including the case where the atomic number ratio of Zn is 5 or more and 7 or less. Further, when the atomic ratio of In:Ga:Zn=1.1:1 or a composition in the vicinity thereof is described, when the atomic ratio of In is 1, the atomic ratio of Ga is greater than 0.1. 2 or less, including the case where the atomic number ratio of Zn is greater than 0.1 and 2 or less.

The transistor included in the circuit 164 and the transistor included in the display portion 162 may have the same structure or different structures. The plurality of transistors included in the circuit 164 may all have the same structure, or may have two or more types. Similarly, the structures of the plurality of transistors included in the display portion 162 may all be the same, or may be of two or more types.

15B and 15C show other configuration examples of the transistor.

The transistor 209 and the transistor 210 each include a conductive layer 221 functioning as a gate, an insulating layer 211 functioning as a gate insulating layer, a semiconductor layer 231 having a channel formation region 231i and a pair of low-resistance regions 231n, and one of the pair of low-resistance regions 231n. a conductive layer 222a connected to a pair of low-resistance regions 231n, a conductive layer 222b connected to the other of a pair of low-resistance regions 231n, an insulating layer 225 functioning as a gate insulating layer, a conductive layer 223 functioning as a gate, and an insulating layer 215 covering the conductive layer 223 have The insulating layer 211 is located between the conductive layer 221 and the channel formation region 231i. The insulating layer 225 is located at least between the conductive layer 223 and the channel formation region 231i. Furthermore, an insulating layer 218 may be provided to cover the transistor.

The transistor 209 shown in FIG. 15B shows an example in which the insulating layer 225 covers the top surface and side surfaces of the semiconductor layer 231 . The

conductive layers

222a and 222b are connected to the low-resistance region 231n through openings provided in the insulating

layers

225 and 215, respectively. One of the

conductive layers

222a and 222b functions as a source and the other functions as a drain.

On the other hand, in the transistor 210 shown in FIG. 15C, the insulating layer 225 overlaps the channel formation region 231i of the semiconductor layer 231 and does not overlap the low resistance region 231n. For example, the structure shown in FIG. 15C can be manufactured by processing the insulating layer 225 using the conductive layer 223 as a mask. In FIG. 15C, the insulating layer 215 is provided to cover the insulating layer 225 and the conductive layer 223, and the

conductive layers

222a and 222b are connected to the low resistance region 231n through openings in the insulating layer 215, respectively.

A connecting portion 204 is provided in a region of the substrate 151 where the substrate 152 does not overlap. At the connecting portion 204 , the wiring 165 is electrically connected to the FPC 172 via the conductive layer 166 and the connecting layer 242 . The conductive layer 166 is a conductive film obtained by processing the same conductive film as the pixel electrode. The conductive layer 166 is exposed on the upper surface of the connecting portion 204 . Thereby, the connecting portion 204 and the FPC 172 can be electrically connected via the connecting layer 242 .

A light shielding layer 148 is preferably provided on the surface of the substrate 152 on the substrate 151 side.

Colored layers

125a and 125b may be provided on the surface of the substrate 152 on the substrate 151 side. In FIG. 15A, the

colored layers

125a and 125b are provided so as to partially cover the light shielding layer 148 when the substrate 152 is used as a reference.

Also, various optical members can be arranged outside the substrate 152 . Examples of optical members include polarizing plates, retardation plates, light diffusion layers (diffusion films, etc.), antireflection layers, light collecting films, and the like. In addition, on the outside of the substrate 152, an antistatic film that suppresses adhesion of dust, a water-repellent film that prevents adhesion of dirt, a hard coat film that suppresses the occurrence of scratches due to use, a shock absorption layer, etc. are arranged. may

By providing the protective layer 131 that covers the light-emitting device, it is possible to suppress the entry of impurities such as water into the light-emitting device and improve the reliability of the light-emitting device.

It is preferable that the insulating layer 215 and the protective layer 131 are in contact with each other through the opening of the insulating layer 214 in the region 228 near the edge of the display device 100A. In particular, it is preferable that the inorganic insulating films are in contact with each other. This can prevent impurities from entering the display section 162 from the outside through the organic insulating film. Therefore, the reliability of the display device 100A can be improved.

For the

substrates

151 and 152, glass, quartz, ceramics, sapphire, resins, metals, alloys, semiconductors, etc. can be used, respectively. A material that transmits the light is used for the substrate on the side from which the light from the light-emitting device is extracted. When flexible materials are used for the

substrates

151 and 152, the flexibility of the display device can be increased and a flexible display can be realized. Alternatively, a polarizing plate may be used as the substrate 151 or the substrate 152 .

As the substrate 151 and the substrate 152, polyester resin such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone ( PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE ) resin, ABS resin, cellulose nanofiber, and the like can be used. One or both of the

substrates

151 and 152 may be made of glass having a thickness sufficient to be flexible.

When a circularly polarizing plate is superimposed on a display device, it is preferable to use a substrate having high optical isotropy as the substrate of the display device. A substrate with high optical isotropy has small birefringence (it can be said that the amount of birefringence is small).

The absolute value of the retardation (retardation) value of the substrate with high optical isotropy is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

Films with high optical isotropy include triacetyl cellulose (TAC, also called cellulose triacetate) films, cycloolefin polymer (COP) films, cycloolefin copolymer (COC) films, and acrylic films.

Also, when a film is used as a substrate, there is a risk that the film will absorb water, causing shape changes such as wrinkles in the display panel. Therefore, it is preferable to use a film having a low water absorption rate as the substrate. For example, it is preferable to use a film with a water absorption of 1% or less, more preferably 0.1% or less, and even more preferably 0.01% or less.

As the adhesive layer 142, various curable adhesives such as photocurable adhesives such as ultraviolet curable adhesives, reaction curable adhesives, thermosetting adhesives, and anaerobic adhesives can be used. These adhesives include epoxy resins, acrylic resins, silicone resins, phenol resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, EVA (ethylene vinyl acetate) resins, and the like. In particular, a material with low moisture permeability such as epoxy resin is preferable. Also, a two-liquid mixed type resin may be used. Alternatively, an adhesive sheet or the like may be used.

As the connection layer 242, an anisotropic conductive film (ACF: Anisotropic Conductive Film), an anisotropic conductive paste (ACP: Anisotropic Conductive Paste), or the like can be used.

In addition to the gate, source and drain of transistors, materials that can be used for conductive layers such as various wirings and electrodes constituting display devices include aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, Examples include metals such as tantalum and tungsten, and alloys containing these metals as main components. A film containing these materials can be used as a single layer or as a laminated structure.

In addition, as the conductive material having translucency, conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, or graphene can be used. Alternatively, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, and titanium, or alloy materials containing such metal materials can be used. Alternatively, a nitride of the metal material (eg, titanium nitride) or the like may be used. Note that when a metal material or an alloy material (or a nitride thereof) is used, it is preferably thin enough to have translucency. Alternatively, a stacked film of any of the above materials can be used as the conductive layer. For example, it is preferable to use a laminated film of a silver-magnesium alloy and indium tin oxide, because the conductivity can be increased. These can also be used for conductive layers such as various wirings and electrodes that constitute a display device, and conductive layers (conductive layers functioning as pixel electrodes or common electrodes) of light-emitting devices.

Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resins and epoxy resins, and inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, and aluminum oxide.

Although FIG. 15A shows an example of a top emission display device 100A in which light is emitted to the substrate 152 side, the present invention is not limited to this. For example, like a display device 100B shown in FIG. 16, a bottom emission display device in which light is emitted to the substrate 151 side may be used.

The display device 100B differs from the display device 100A in that

colored layers

125a and 125b are provided between the insulating layer 213 and the insulating layer 214 . The

colored layers

125a and 125b are provided so as to overlap the

light emitting devices

130a and 130b, respectively.

The display device 100B also differs from the display device 100A in that the

pixel electrodes

111a and 111b contain a material that transmits visible light, and the common electrode 115 contains a material that reflects visible light. Here, the conductive layer 166 obtained by processing the same conductive film as the

pixel electrodes

111a and 111b also contains a material that transmits visible light.

Also, in the display device 100B, the substrate 151 is made of a material having high visible light transmittance.

With the above configuration, light emitted from the light emitting layers of the

light emitting devices

130a and 130b passes through the

pixel electrodes

111a and 111b and the

colored layers

125a and 125b, respectively, and is emitted from the substrate 151 side. .

This embodiment can be implemented by appropriately combining at least part of it with other embodiments described herein.

(Embodiment 3)
In this embodiment, a structure example of a display module including a display device of one embodiment of the present invention will be described.

17A is a schematic perspective view of the display module 480. FIG. Display module 480 has display device 400 and FPC 490 .

The display module 480 has

substrates

401 and 402 . A display portion 481 is provided on the substrate 402 side. The display section 481 is an area for displaying an image in the display module 480, and is an area where light from each pixel provided in the pixel section 484, which will be described later, can be visually recognized.

FIG. 17B shows a perspective view schematically showing the configuration on the substrate 401 side. The substrate 401 has a structure in which a circuit portion 482, a pixel circuit portion 483 over the circuit portion 482, and a pixel portion 484 over the pixel circuit portion 483 are stacked. In addition, a terminal portion 485 for connecting to the FPC 490 is provided on a portion of the substrate 401 that does not overlap with the pixel portion 484 . Also, the terminal portion 485 and the circuit portion 482 are electrically connected by a wiring portion 486 composed of a plurality of wirings.

The pixel unit 484 has a plurality of periodically arranged pixels 484a. An enlarged view of one pixel 484a is shown on the right side of FIG. 17B. Pixel 484a has sub-pixel 110a, sub-pixel 110b, and sub-pixel 110c. The above embodiment can be referred to for the configuration of the sub-pixel 110a, the sub-pixel 110b, and the sub-pixel 110c and their surroundings.

The pixel circuit section 483 has a plurality of pixel circuits 483a arranged periodically. The plurality of pixels 484a and the plurality of pixel circuits 483a may be arranged in a stripe arrangement as shown in FIG. 17B. Note that the plurality of pixels 484a and the plurality of pixel circuits 483a may be arranged in a delta arrangement or the like, instead of the stripe arrangement.

One pixel circuit 483a is a circuit that controls light emission of three light emitting elements included in one pixel 484a. One pixel circuit 483a may have a structure in which three circuits for controlling light emission of one light-emitting element are provided. For example, the pixel circuit 483a can have at least one selection transistor, one current control transistor (driving transistor), and a capacitive element for each light emitting element. At this time, a gate signal is input to the gate of the selection transistor, and a source signal is input to either the source or the drain of the selection transistor. This realizes an active matrix display device.

The circuit section 482 has a circuit that drives each pixel circuit 483 a of the pixel circuit section 483 . For example, it is preferable to have a gate line driver circuit, a source line driver circuit, and the like. In addition, an arithmetic circuit, a memory circuit, a power supply circuit, and the like may be provided.

The FPC 490 functions as wiring for supplying a video signal, power supply potential, or the like to the circuit section 482 from the outside. Also, an IC may be mounted on the FPC 490 .

Since the display module 480 can have a structure in which the pixel circuit portion 483, the circuit portion 482, or the like is stacked under the pixel portion 484, the aperture ratio (effective display area ratio) of the display portion 481 can be extremely high. can be done. For example, the aperture ratio of the display portion 481 can be 40% or more and less than 100%, preferably 50% or more and 95% or less, more preferably 60% or more and 95% or less. In addition, the pixels 484a can be arranged at an extremely high density, and the definition of the display portion 481 can be extremely high. For example, in the display portion 481, the pixels 484a may be arranged with a resolution of 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and still more preferably 6000 ppi or more, and 20000 ppi or less, or 30000 ppi or less. preferable.

Since such a display module 480 has extremely high definition, it can be suitably used for devices for VR such as head-mounted displays, or glasses-type devices for AR. For example, even in a configuration in which the display portion of the display module 480 is viewed through a lens, the display module 480 has an extremely high-definition display portion 481, so pixels cannot be viewed even if the display portion is enlarged with the lens. , a highly immersive display can be performed. Moreover, the display module 480 is not limited to this, and can be suitably used for electronic equipment having a relatively small display unit. For example, it can be suitably used for a display part of a wearable electronic device such as a wristwatch.

The structure of each display device (the display device 400A to the display device 400C) that can be used for the display device 400 will be described below.

[Configuration example 1]
FIG. 18A is a schematic cross-sectional view of the display device 400A.

The display device 400A includes a substrate 401,

subpixels

110a, 110b, 110c, capacitive elements 440, transistors 410, and the like.

A layered structure from the substrate 401 to the capacitive element 440 corresponds to the layer 101 including the transistor in the first embodiment.

A transistor 410 is a transistor in which a channel formation region is formed in the substrate 401 . As the substrate 401, for example, a semiconductor substrate such as a single crystal silicon substrate can be used. The transistor 410 includes part of the substrate 401, a conductive layer 411, a low-resistance region 412, an insulating layer 413, an insulating layer 414, and the like. The conductive layer 411 functions as a gate electrode. An insulating layer 413 is located between the substrate 401 and the conductive layer 411 and functions as a gate insulating layer. The low-resistance region 412 is a region in which impurities are doped in the substrate 401 and functions as either a source or a drain. The insulating layer 414 is provided to cover the side surface of the conductive layer 411 .

A device isolation layer 415 is provided between two adjacent transistors 410 so as to be embedded in the substrate 401 .

An insulating layer 461 is provided to cover the transistor 410 , and a capacitor 440 is provided over the insulating layer 461 .

The capacitive element 440 has a conductive layer 441, a conductive layer 442, and an insulating layer 443 positioned therebetween. The conductive layer 441 functions as one electrode of the capacitor 440 , the conductive layer 442 functions as the other electrode of the capacitor 440 , and the insulating layer 443 functions as the dielectric of the capacitor 440 .

The conductive layer 441 is provided on the insulating layer 461 and electrically connected to one of the source and drain of the transistor 410 by a plug 471 embedded in the insulating layer 461 . An insulating layer 443 is provided over the conductive layer 441 . The conductive layer 442 is provided in a region overlapping with the conductive layer 441 with the insulating layer 443 provided therebetween.

An insulating layer 321 is provided to cover the capacitive element 440 , and sub-pixels 110 a , 110 b , 110 c and the like are provided on the insulating layer 321 . The pixel electrodes of the sub-pixel 110 a , sub-pixel 110 b , and sub-pixel 110 c are electrically connected to the conductive layer 441 by plugs 331 embedded in the insulating

layers

321 and 443 . Here, an example using the configuration illustrated in FIG. 1B is shown as the configuration of the sub-pixel 110a, the sub-pixel 110b, the sub-pixel 110c, etc., but the configuration is not limited to this, and various configurations illustrated above can be applied. be able to.

In the display device 400A, a protective layer 131, an insulating layer 362, and an insulating layer 363 are provided in this order so as to cover the common electrode 115 of the light emitting elements of the

subpixels

110a, 110b, and 110c. These three insulating layers function as protective layers that prevent impurities such as water from diffusing into the light emitting elements of the

subpixels

110a, 110b, and 110c. An inorganic insulating film with low moisture permeability such as a silicon oxide film, a silicon nitride film, or an aluminum oxide film is preferably used for the insulating layer 363 . Alternatively, an organic insulating film with high light-transmitting property can be used for the insulating layer 362 . By using an organic insulating film for the insulating layer 362, the influence of unevenness on the lower side of the insulating layer 362 can be reduced, and the surface on which the insulating layer 363 is formed can be made smooth. As a result, defects such as pinholes are less likely to occur in the insulating layer 363, and the moisture permeability of the protective layer can be further increased. The structure of the protective layer covering the light-emitting elements of the sub-pixels 110a, 110b, and 110c is not limited to this, and may be a single-layer structure, a two-layer structure, or a laminated structure of four or more layers.

The display device 400A has a substrate 402 on the viewing side. The substrate 402 and the substrate 401 are bonded together with an adhesive layer 364 having translucency. As the substrate 402, a light-transmitting substrate such as a glass substrate, a quartz substrate, a sapphire substrate, or a plastic substrate can be used.

With such a configuration, a display device with extremely high definition and high display quality can be realized.

[Configuration example 2]
FIG. 19 is a schematic cross-sectional view of the display device 400B. The display device 400B mainly differs from the display device 400A in that the transistor configuration is different.

The transistor 420 is a transistor in which a metal oxide (also referred to as an oxide semiconductor) is applied to a semiconductor layer in which a channel is formed.

The transistor 420 includes a semiconductor layer 421, an insulating layer 423, a conductive layer 424, a pair of conductive layers 425, an insulating layer 426, a conductive layer 427, and the like.

As the substrate 401 provided with the transistor 420, the insulating substrate or the semiconductor substrate described above can be used.

An insulating layer 432 is provided on the substrate 401 . The insulating layer 432 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 401 into the transistor 420 and oxygen from the semiconductor layer 421 toward the insulating layer 432 side. As the insulating layer 432, a film into which hydrogen or oxygen is less likely to diffuse than a silicon oxide film, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film, can be used.

A conductive layer 427 is provided over the insulating layer 432 and an insulating layer 426 is provided to cover the conductive layer 427 . The conductive layer 427 functions as a first gate electrode of the transistor 420, and part of the insulating layer 426 functions as a first gate insulating layer. An oxide insulating film such as a silicon oxide film is preferably used for at least a portion of the insulating layer 426 which is in contact with the semiconductor layer 421 . The upper surface of the insulating layer 426 is preferably planarized.

The semiconductor layer 421 is provided on the insulating layer 426 . The semiconductor layer 421 preferably includes a metal oxide (also referred to as an oxide semiconductor) film having semiconductor characteristics. Details of materials that can be suitably used for the semiconductor layer 421 will be described later.

A pair of conductive layers 425 are provided on and in contact with the semiconductor layer 421 and function as a source electrode and a drain electrode.

An insulating layer 428 is provided to cover the top and side surfaces of the pair of conductive layers 425, the side surface of the semiconductor layer 421, and the like, and the insulating layer 461b is provided over the insulating layer 428. The insulating layer 428 functions as a barrier insulating film that prevents impurities such as water or hydrogen from diffusing into the semiconductor layer 421 from the insulating layer 461 b or the like and oxygen from leaving the semiconductor layer 421 . As the insulating layer 428, an insulating film similar to the insulating layer 432 can be used.

An opening reaching the semiconductor layer 421 is provided in the insulating layer 428 and the insulating layer 461b. The insulating layer 423 and the conductive layer 424 are embedded in the opening, which are in contact with the side surfaces of the insulating layer 461b, the insulating layer 428, and the conductive layer 425, and the top surface of the semiconductor layer 421. FIG. The conductive layer 424 functions as a second gate electrode, and the insulating layer 423 functions as a second gate insulating layer.

The top surface of the conductive layer 424, the top surface of the insulating layer 423, and the top surface of the insulating layer 461b are planarized so that their heights are approximately the same, and the insulating

layers

429 and 461a are provided to cover them. .

The insulating

layers

461a and 461b function as interlayer insulating layers. The insulating layer 429 also functions as a barrier insulating film that prevents impurities such as water or hydrogen from diffusing into the transistor 420 from the insulating layer 461a or the like. As the insulating layer 429, an insulating film similar to the insulating

layers

428 and 432 can be used.

A plug 471 electrically connected to one of the pair of conductive layers 425 is provided so as to be embedded in the insulating

layers

461a, 429, and 461b. Here, the plug 471 includes the conductive layer 471a covering the side surfaces of the openings of the insulating

layers

461a, 461b, 429, and 428 and part of the top surface of the conductive layer 425, and the conductive layer 471a. It is preferable to have a conductive layer 471b in contact with the top surface. At this time, a conductive material into which hydrogen and oxygen are difficult to diffuse is preferably used for the conductive layer 471a.

[Configuration example 3]
FIG. 20 is a schematic cross-sectional view of the display device 400C. The display device 400C has a structure in which a transistor 410 in which a channel is formed over a substrate 401 and a transistor 420 including a metal oxide in a semiconductor layer in which the channel is formed are stacked.

An insulating layer 461 is provided to cover the transistor 410 , and a conductive layer 451 is provided over the insulating layer 461 . An insulating layer 462 is provided to cover the conductive layer 451 , and the conductive layer 452 is provided over the insulating layer 462 . Each of the

conductive layers

451 and 452 functions as a wiring. An insulating layer 463 and an insulating layer 432 are provided to cover the conductive layer 452 , and the transistor 420 is provided over the insulating layer 432 . An insulating layer 465 is provided to cover the transistor 420 , and the capacitor 440 is provided over the insulating layer 465 . The capacitor 440 and the transistor 420 are electrically connected through a plug 474 .

The transistor 420 can be used as a transistor forming a pixel circuit. Further, the transistor 410 can be used as a transistor forming a pixel circuit or a transistor forming a driver circuit (a gate line driver circuit or a source line driver circuit) for driving the pixel circuit. Further, the

transistors

410 and 420 can be used as transistors included in various circuits such as an arithmetic circuit and a memory circuit.

With such a structure, not only the pixel circuit but also the driver circuit and the like can be formed directly under the light-emitting unit, so that the size of the display device can be reduced compared to the case where the driver circuit is provided around the display region. becomes possible.

Components such as transistors applicable to the display device will be described below.

[transistor]
A transistor includes a conductive layer functioning as a gate electrode, a semiconductor layer, a conductive layer functioning as a source electrode, a conductive layer functioning as a drain electrode, and an insulating layer functioning as a gate insulating layer.

Note that there is no particular limitation on the structure of the transistor included in the display device of one embodiment of the present invention. For example, a planar transistor, a staggered transistor, or an inverted staggered transistor may be used. Further, the transistor structure may be either a top-gate type or a bottom-gate type. Alternatively, gate electrodes may be provided above and below the channel.

A transistor (OS transistor) in which a metal oxide film is used as a semiconductor layer in which a channel is formed will be described below.

A metal oxide having an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more can be used as a semiconductor material used for a transistor. A typical example is a metal oxide containing indium, and for example, CAC-OS, which will be described later, can be used.

A transistor using a metal oxide, which has a wider bandgap and a lower carrier density than silicon, retains charge accumulated in a capacitor connected in series with the transistor for a long period of time due to its low off-state current. It is possible.

The semiconductor layer is represented by an In-M-Zn oxide containing, for example, indium, zinc, and M (M is a metal such as aluminum, titanium, gallium, germanium, yttrium, zirconium, lanthanum, cerium, tin, neodymium, or hafnium). It can be a membrane that is

When the metal oxide forming the semiconductor layer is an In-M-Zn-based oxide, the atomic ratio of the metal elements in the sputtering target used for forming the In-M-Zn oxide is In≧M, Zn It is preferable to satisfy ≧M. The atomic ratios of the metal elements in such a sputtering target are In:M:Zn=1:1:1, In:M:Zn=1:1:1.2, In:M:Zn=3:1: 2, In:M:Zn=4:2:3, In:M:Zn=4:2:4.1, In:M:Zn=5:1:6, In:M:Zn=5:1: 7, In:M:Zn=5:1:8, etc. are preferable. It should be noted that the atomic ratio of the semiconductor layers to be deposited includes a variation of plus or minus 40% of the atomic ratio of the metal element contained in the sputtering target.

[Conductive layer]
In addition to the gate, source and drain of transistors, materials that can be used for conductive layers such as various wirings and electrodes constituting display devices include aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, A metal such as tantalum or tungsten, or an alloy containing this as a main component can be used. Also, a film containing these materials can be used as a single layer or as a laminated structure. For example, a single-layer structure of an aluminum film containing silicon, a two-layer structure in which an aluminum film is stacked over a titanium film, a two-layer structure in which an aluminum film is stacked over a tungsten film, and a copper film over a copper-magnesium-aluminum alloy film. A two-layer structure, a two-layer structure in which a copper film is laminated on a titanium film, a two-layer structure in which a copper film is laminated on a tungsten film, a titanium film or a titanium nitride film, and an aluminum film or a copper film overlaid thereon and further a titanium film or a titanium nitride film is formed thereon, a molybdenum film or a molybdenum nitride film is laminated thereon, an aluminum film or a copper film is laminated thereon, and a molybdenum film or a There is a three-layer structure that forms a molybdenum nitride film, and the like. Note that an oxide such as indium oxide, tin oxide, or zinc oxide may be used. Further, it is preferable to use copper containing manganese because the controllability of the shape by etching is increased.

[Insulating layer]
Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resins and epoxy resins, resins having a siloxane bond such as silicone, silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, and oxide. Inorganic insulating materials such as aluminum can also be used.

Further, the light emitting element is preferably provided between a pair of insulating films (barrier insulating films) with low water permeability. As a result, it is possible to prevent impurities such as water from entering the light-emitting element, and to prevent deterioration of the reliability of the device.

Examples of insulating films with low water permeability include films containing nitrogen and silicon such as silicon nitride films and silicon nitride oxide films, and films containing nitrogen and aluminum such as aluminum nitride films. Alternatively, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, or the like may be used.

For example, the water vapor permeation amount of an insulating film with low water permeability is 1×10 ⁻⁵ [g/(m ² ·day)] or less, preferably 1×10 ⁻⁶ [g/(m ² ·day)] or less, It is more preferably 1×10 ⁻⁷ [g/(m ² ·day)] or less, still more preferably 1×10 ⁻⁸ [g/(m ² ·day)] or less.

(Embodiment 4)
In this embodiment, a metal oxide (also referred to as an oxide semiconductor) that can be used for the OS transistor described in the above embodiment will be described.

The metal oxide preferably contains at least indium or zinc. In particular, it preferably contains indium and zinc. In addition to these, aluminum, gallium, yttrium, tin and the like are preferably contained. In addition, one or more selected from boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, cobalt, etc. may be contained. .

In addition, the metal oxide is formed by chemical vapor deposition (CVD) such as sputtering, metal organic chemical vapor deposition (MOCVD), or atomic layer deposition (ALD). It can be formed by a layer deposition method or the like.

<Classification of crystal structure>
Crystal structures of oxide semiconductors include amorphous (including completely amorphous), CAAC (c-axis-aligned crystalline), nc (nanocrystalline), CAC (cloud-aligned composite), single crystal, and polycrystal. (poly crystal) and the like.

The crystal structure of the film or substrate can be evaluated using an X-ray diffraction (XRD) spectrum. For example, it can be evaluated using an XRD spectrum obtained by GIXD (Grazing-Incidence XRD) measurement. The GIXD method is also called a thin film method or a Seemann-Bohlin method.

For example, in a quartz glass substrate, the shape of the peak of the XRD spectrum is almost bilaterally symmetrical. On the other hand, in an IGZO film having a crystalline structure, the peak shape of the XRD spectrum is left-right asymmetric. The asymmetric shape of the peaks in the XRD spectra demonstrates the presence of crystals in the film or substrate. In other words, the film or substrate cannot be said to be in an amorphous state unless the shape of the peaks in the XRD spectrum is symmetrical.

In addition, the crystal structure of the film or substrate can be evaluated by a diffraction pattern (also referred to as a nano beam electron diffraction pattern) observed by nano beam electron diffraction (NBED). For example, a halo is observed in the diffraction pattern of a quartz glass substrate, and it can be confirmed that the quartz glass is in an amorphous state. Also, in the diffraction pattern of the IGZO film formed at room temperature, a spot-like pattern is observed instead of a halo. Therefore, it is presumed that the IGZO film deposited at room temperature is neither crystalline nor amorphous, but in an intermediate state and cannot be concluded to be in an amorphous state.

<<Structure of Oxide Semiconductor>>
Note that oxide semiconductors may be classified differently from the above when their structures are focused. For example, oxide semiconductors are classified into single-crystal oxide semiconductors and non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the above CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, amorphous-like oxide semiconductors (a-like OS), amorphous oxide semiconductors, and the like.

Here, the details of the above-mentioned CAAC-OS, nc-OS, and a-like OS will be explained.

[CAAC-OS]
A CAAC-OS is an oxide semiconductor that includes a plurality of crystal regions, and the c-axes of the plurality of crystal regions are oriented in a specific direction. Note that the specific direction is the thickness direction of the CAAC-OS film, the normal direction to the formation surface of the CAAC-OS film, or the normal direction to the surface of the CAAC-OS film. A crystalline region is a region having periodicity in atomic arrangement. If the atomic arrangement is regarded as a lattice arrangement, the crystalline region is also a region with a uniform lattice arrangement. Furthermore, CAAC-OS has a region where a plurality of crystal regions are connected in the a-b plane direction, and the region may have strain. The strain refers to a portion where the orientation of the lattice arrangement changes between a region with a uniform lattice arrangement and another region with a uniform lattice arrangement in a region where a plurality of crystal regions are connected. That is, CAAC-OS is an oxide semiconductor that is c-axis oriented and has no obvious orientation in the ab plane direction.

Note that each of the plurality of crystal regions is composed of one or more microcrystals (crystals having a maximum diameter of less than 10 nm). When the crystalline region is composed of one minute crystal, the maximum diameter of the crystalline region is less than 10 nm. Moreover, when a crystal region is composed of a large number of microscopic crystals, the size of the crystal region may be about several tens of nanometers.

In the In-M-Zn oxide (element M is one or more selected from aluminum, gallium, yttrium, tin, titanium, and the like), CAAC-OS contains indium (In) and oxygen. A tendency to have a layered crystal structure (also referred to as a layered structure) in which a layer (hereinafter referred to as an In layer) and a layer containing the element M, zinc (Zn), and oxygen (hereinafter referred to as a (M, Zn) layer) are stacked. There is Note that indium and the element M can be substituted with each other. Therefore, the (M, Zn) layer may contain indium. In some cases, the In layer contains the element M. Note that the In layer may contain Zn. The layered structure is observed as a lattice image in, for example, a high-resolution TEM (Transmission Electron Microscope) image.

When structural analysis is performed on the CAAC-OS film using, for example, an XRD device, the out-of-plane XRD measurement using a θ/2θ scan shows that the peak indicating the c-axis orientation is at or near 2θ=31°. detected at Note that the position of the peak indicating the c-axis orientation (value of 2θ) may vary depending on the type and composition of the metal elements forming the CAAC-OS.

Also, for example, a plurality of bright points (spots) are observed in the electron beam diffraction pattern of the CAAC-OS film. A certain spot and another spot are observed at point-symmetrical positions with respect to the spot of the incident electron beam that has passed through the sample (also referred to as a direct spot) as the center of symmetry.

When the crystal region is observed from the above specific direction, the lattice arrangement in the crystal region is basically a hexagonal lattice, but the unit cell is not always a regular hexagon and may be a non-regular hexagon. Moreover, the distortion may have a lattice arrangement such as a pentagon or a heptagon. Note that in CAAC-OS, no clear crystal grain boundary can be observed even near the strain. That is, it can be seen that the distortion of the lattice arrangement suppresses the formation of grain boundaries. This is because the CAAC-OS can tolerate strain due to the fact that the arrangement of oxygen atoms is not dense in the ab plane direction and the bond distance between atoms changes due to the substitution of metal atoms. it is conceivable that.

A crystal structure in which clear grain boundaries are confirmed is called a polycrystal. A grain boundary becomes a recombination center, traps carriers, and is highly likely to cause a decrease in on-current of a transistor, a decrease in field-effect mobility, and the like. Therefore, a CAAC-OS in which no clear grain boundaries are observed is one of crystalline oxides having a crystal structure suitable for a semiconductor layer of a transistor. Note that a structure containing Zn is preferable for forming a CAAC-OS. For example, In--Zn oxide and In--Ga--Zn oxide are preferable because they can suppress the generation of grain boundaries more than In oxide.

CAAC-OS is an oxide semiconductor with high crystallinity and no clear crystal grain boundaries. Therefore, it can be said that the decrease in electron mobility due to grain boundaries is less likely to occur in CAAC-OS. In addition, since the crystallinity of an oxide semiconductor may be deteriorated by contamination of impurities, generation of defects, or the like, a CAAC-OS can be said to be an oxide semiconductor with few impurities and defects (such as oxygen vacancies). Therefore, an oxide semiconductor including CAAC-OS has stable physical properties. Therefore, an oxide semiconductor including CAAC-OS is resistant to heat and has high reliability. CAAC-OS is also stable against high temperatures (so-called thermal budget) in the manufacturing process. Therefore, the use of the CAAC-OS for the OS transistor makes it possible to increase the degree of freedom in the manufacturing process.

[nc-OS]
The nc-OS has periodic atomic arrangement in a minute region (eg, a region of 1 nm to 10 nm, particularly a region of 1 nm to 3 nm). In other words, the nc-OS has minute crystals. In addition, since the size of the minute crystal is, for example, 1 nm or more and 10 nm or less, particularly 1 nm or more and 3 nm or less, the minute crystal is also called a nanocrystal. In addition, nc-OS does not show regularity in crystal orientation between different nanocrystals. Therefore, no orientation is observed in the entire film. Therefore, an nc-OS may be indistinguishable from an a-like OS or an amorphous oxide semiconductor depending on the analysis method. For example, when an nc-OS film is subjected to structural analysis using an XRD apparatus, out-of-plane XRD measurement using θ/2θ scanning does not detect a peak indicating crystallinity. Further, when an nc-OS film is subjected to electron beam diffraction (also referred to as selected area electron beam diffraction) using an electron beam with a probe diameter larger than that of nanocrystals (for example, 50 nm or more), a diffraction pattern such as a halo pattern is obtained. is observed. On the other hand, when an nc-OS film is subjected to electron diffraction (also referred to as nanobeam electron diffraction) using an electron beam with a probe diameter close to or smaller than the size of a nanocrystal (for example, 1 nm or more and 30 nm or less), An electron beam diffraction pattern may be obtained in which a plurality of spots are observed within a ring-shaped area centered on the direct spot.

[a-like OS]
An a-like OS is an oxide semiconductor having a structure between an nc-OS and an amorphous oxide semiconductor. An a-like OS has void or low density regions. That is, the a-like OS has lower crystallinity than the nc-OS and CAAC-OS. In addition, the a-like OS has a higher hydrogen concentration in the film than the nc-OS and the CAAC-OS.

<<Structure of Oxide Semiconductor>>
Next, the details of the above CAC-OS will be described. Note that CAC-OS relates to material composition.

[CAC-OS]
A CAC-OS is, for example, one structure of a material in which elements constituting a metal oxide are unevenly distributed with a size of 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 3 nm or less, or in the vicinity thereof. In the following, in the metal oxide, one or more metal elements are unevenly distributed, and the region having the metal element has a size of 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 3 nm or less, or a size in the vicinity thereof. The mixed state is also called mosaic or patch.

Furthermore, the CAC-OS is a structure in which the material is separated into a first region and a second region to form a mosaic shape, and the first region is distributed in the film (hereinafter, also referred to as a cloud shape). ). That is, CAC-OS is a composite metal oxide in which the first region and the second region are mixed.

Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in the In--Ga--Zn oxide are denoted by [In], [Ga], and [Zn], respectively. For example, in the CAC-OS in In—Ga—Zn oxide, the first region is a region where [In] is larger than [In] in the composition of the CAC-OS film. The second region is a region where [Ga] is greater than [Ga] in the composition of the CAC-OS film. Alternatively, for example, the first region is a region in which [In] is larger than [In] in the second region and [Ga] is smaller than [Ga] in the second region. The second region is a region in which [Ga] is larger than [Ga] in the first region and [In] is smaller than [In] in the first region.

Specifically, the first region is a region whose main component is indium oxide, indium zinc oxide, or the like. The second region is a region containing gallium oxide, gallium zinc oxide, or the like as a main component. That is, the first region can be rephrased as a region containing In as a main component. Also, the second region can be rephrased as a region containing Ga as a main component.

A clear boundary between the first region and the second region may not be observed.

In addition, the CAC-OS in the In—Ga—Zn oxide means a region containing Ga as a main component and a region containing In as a main component in a material structure containing In, Ga, Zn, and O. Each region is a mosaic, and refers to a configuration in which these regions exist randomly. Therefore, CAC-OS is presumed to have a structure in which metal elements are unevenly distributed.

The CAC-OS can be formed, for example, by sputtering under the condition that the substrate is not heated. When the CAC-OS is formed by a sputtering method, one or more selected from an inert gas (typically argon), an oxygen gas, and a nitrogen gas may be used as a deposition gas. good. In addition, the lower the flow rate ratio of the oxygen gas to the total flow rate of the film formation gas during film formation, the better. is preferably 0% or more and 10% or less.

Further, for example, in the CAC-OS in In-Ga-Zn oxide, an EDX mapping obtained using energy dispersive X-ray spectroscopy (EDX) shows that a region containing In as a main component It can be confirmed that the (first region) and the region (second region) containing Ga as the main component are unevenly distributed and have a mixed structure.

Here, the first region is a region with higher conductivity than the second region. That is, when carriers flow through the first region, conductivity as a metal oxide is developed. Therefore, by distributing the first region in the form of a cloud in the metal oxide, a high field effect mobility (μ) can be realized.

On the other hand, the second region is a region with higher insulation than the first region. In other words, the leakage current can be suppressed by distributing the second region in the metal oxide.

Therefore, when the CAC-OS is used for a transistor, the conductivity caused by the first region and the insulation caused by the second region act in a complementary manner to provide a switching function (turning ON/OFF). functions) can be given to the CAC-OS. In other words, in CAC-OS, a part of the material has a conductive function, a part of the material has an insulating function, and the whole material has a semiconductor function. By separating the conductive and insulating functions, both functions can be maximized. Therefore, by using a CAC-OS for a transistor, high on-state current (I _on ), high field-effect mobility (μ), and favorable switching operation can be achieved.

In addition, a transistor using a CAC-OS has high reliability. Therefore, CAC-OS is most suitable for various semiconductor devices including display devices.

Oxide semiconductors have a variety of structures, each with different characteristics. An oxide semiconductor of one embodiment of the present invention includes two or more of an amorphous oxide semiconductor, a polycrystalline oxide semiconductor, an a-like OS, a CAC-OS, an nc-OS, and a CAAC-OS. may

<Transistor including oxide semiconductor>
Next, the case where the above oxide semiconductor is used for a transistor is described.

By using the above oxide semiconductor for a transistor, a transistor with high field-effect mobility can be realized. Further, a highly reliable transistor can be realized.

An oxide semiconductor with low carrier concentration is preferably used for a transistor. For example, the carrier concentration of the oxide semiconductor is 1×10 ¹⁷ cm ⁻³ or less, preferably 1×10 ¹⁵ cm ⁻³ or less, more preferably 1×10 ¹³ cm ⁻³ or less, more preferably 1×10 ¹¹ cm ⁻³ or less. ³ or less, more preferably less than 1×10 ¹⁰ cm ⁻³ and 1×10 ⁻⁹ cm ⁻³ or more. Note that in the case of lowering the carrier concentration of the oxide semiconductor film, the impurity concentration in the oxide semiconductor film may be lowered to lower the defect level density. In this specification and the like, a low impurity concentration and a low defect level density are referred to as high-purity intrinsic or substantially high-purity intrinsic. Note that an oxide semiconductor with a low carrier concentration is sometimes referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor.

In addition, since a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a low defect level density, the trap level density may also be low.

In addition, the charge trapped in the trap level of the oxide semiconductor takes a long time to disappear, and may behave as if it were a fixed charge. Therefore, a transistor whose channel formation region is formed in an oxide semiconductor with a high trap level density might have unstable electrical characteristics.

Therefore, in order to stabilize the electrical characteristics of a transistor, it is effective to reduce the impurity concentration in the oxide semiconductor. In order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in adjacent films. Impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, silicon, and the like.

<Impurities>
Here, the influence of each impurity in the oxide semiconductor is described.

When an oxide semiconductor contains silicon or carbon, which is one of Group 14 elements, a defect level is formed in the oxide semiconductor. Therefore, the concentration of silicon or carbon in the oxide semiconductor and the concentration of silicon or carbon in the vicinity of the interface with the oxide semiconductor (concentration obtained by secondary ion mass spectrometry (SIMS)) are 2 ×10 ¹⁸ atoms/cm ³ or less, preferably 2 × 10 ¹⁷ atoms/cm ³ or less.

Further, when an oxide semiconductor contains an alkali metal or an alkaline earth metal, a defect level may be formed to generate carriers. Therefore, a transistor using an oxide semiconductor containing an alkali metal or an alkaline earth metal is likely to have normally-on characteristics. Therefore, the concentration of alkali metal or alkaline earth metal in the oxide semiconductor obtained by SIMS is set to 1×10 ¹⁸ atoms/cm ³ or less, preferably 2×10 ¹⁶ atoms/cm ³ or less.

In addition, when an oxide semiconductor contains nitrogen, electrons as carriers are generated, the carrier concentration increases, and the oxide semiconductor tends to be n-type. As a result, a transistor including an oxide semiconductor containing nitrogen as a semiconductor tends to have normally-on characteristics. Alternatively, when an oxide semiconductor contains nitrogen, a trap level may be formed. As a result, the electrical characteristics of the transistor may become unstable. Therefore, the nitrogen concentration in the oxide semiconductor obtained by SIMS is less than 5×10 ¹⁹ atoms/cm ³ , preferably 5×10 ¹⁸ atoms/cm ³ or less, more preferably 1×10 ¹⁸ atoms/cm ³ or less. , more preferably 5×10 ¹⁷ atoms/cm ³ or less.

Further, hydrogen contained in the oxide semiconductor reacts with oxygen that bonds to a metal atom to form water, which may cause oxygen vacancies. When hydrogen enters the oxygen vacancies, electrons, which are carriers, may be generated. In addition, part of hydrogen may bond with oxygen that bonds with a metal atom to generate an electron, which is a carrier. Therefore, a transistor including an oxide semiconductor containing hydrogen is likely to have normally-on characteristics. Therefore, hydrogen in the oxide semiconductor is preferably reduced as much as possible. Specifically, in the oxide semiconductor, the hydrogen concentration obtained by SIMS is less than 1×10 ²⁰ atoms/cm ³ , preferably less than 1×10 ¹⁹ atoms/cm ³ , more preferably less than 5×10 ¹⁸ atoms/cm. Less than ³ , more preferably less than 1×10 ¹⁸ atoms/cm ³ .

By using an oxide semiconductor in which impurities are sufficiently reduced for a channel formation region of a transistor, stable electrical characteristics can be imparted.

This embodiment can be appropriately combined with other embodiments.

(Embodiment 5)
In this embodiment, an electronic device of one embodiment of the present invention will be described with reference to FIGS.

An electronic device of this embodiment includes the display device of one embodiment of the present invention in a display portion. The display device of one embodiment of the present invention can easily have high definition and high resolution. Therefore, it can be used for display portions of various electronic devices.

Examples of electronic devices include televisions, desktop or notebook personal computers, monitors for computers, digital signage, large game machines such as pachinko machines, and other electronic devices with relatively large screens. Examples include cameras, digital video cameras, digital photo frames, mobile phones, mobile game machines, mobile information terminals, and sound reproducing devices.

In particular, since the display device of one embodiment of the present invention can have high definition, it can be suitably used for an electronic device having a relatively small display portion. Examples of such electronic devices include wristwatch-type and bracelet-type information terminals (wearable devices), VR devices such as head-mounted displays, glasses-type AR devices, and MR devices. A wearable device that can be attached to a part is exemplified.

A display device of one embodiment of the present invention includes HD (1280×720 pixels), FHD (1920×1080 pixels), WQHD (2560×1440 pixels), WQXGA (2560×1600 pixels), 4K (2560×1600 pixels), 3840×2160) and 8K (7680×4320 pixels). In particular, it is preferable to set the resolution to 4K, 8K, or higher. Further, the pixel density (definition) of the display device of one embodiment of the present invention is preferably 100 ppi or more, preferably 300 ppi or more, more preferably 500 ppi or more, more preferably 1000 ppi or more, more preferably 2000 ppi or more, and 3000 ppi or more. More preferably, it is 5000 ppi or more, and even more preferably 7000 ppi or more. By using a display device having one or both of high resolution and high definition in this way, it is possible to further enhance the sense of realism and the sense of depth in electronic devices for personal use such as portable or home use. . Further, there is no particular limitation on the screen ratio (aspect ratio) of the display device of one embodiment of the present invention. For example, the display device can support various screen ratios such as 1:1 (square), 4:3, 16:9, 16:10.

The electronic device of this embodiment includes sensors (force, displacement, position, velocity, acceleration, angular velocity, number of revolutions, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage , power, radiation, flow, humidity, gradient, vibration, odor or infrared).

The electronic device of this embodiment can have various functions. For example, functions to display various information (still images, moving images, text images, etc.) on the display, touch panel functions, functions to display calendars, dates or times, functions to execute various software (programs), wireless communication function, a function of reading a program or data recorded on a recording medium, and the like.

An electronic device 6500 shown in FIG. 21A is a mobile information terminal that can be used as a smartphone.

The electronic device 6500 has a housing 6501, a display unit 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, a light source 6508, and the like. A display portion 6502 has a touch panel function.

The display device of one embodiment of the present invention can be applied to the display portion 6502 .

FIG. 21B is a schematic cross-sectional view including the end of the housing 6501 on the microphone 6506 side.

A light-transmitting protective member 6510 is provided on the display surface side of the housing 6501, and a display panel 6511, an optical member 6512, a touch sensor panel 6513, and a printer are placed in a space surrounded by the housing 6501 and the protective member 6510. A substrate 6517, a battery 6518, and the like are arranged.

A display panel 6511, an optical member 6512, and a touch sensor panel 6513 are fixed to the protective member 6510 with an adhesive layer (not shown).

A portion of the display panel 6511 is folded back in a region outside the display portion 6502, and the FPC 6515 is connected to the folded portion. An IC6516 is mounted on the FPC6515. The FPC 6515 is connected to terminals provided on the printed circuit board 6517 .

The flexible display of one embodiment of the present invention can be applied to the display panel 6511 . Therefore, an extremely lightweight electronic device can be realized. In addition, since the display panel 6511 is extremely thin, the thickness of the electronic device can be reduced and the large-capacity battery 6518 can be mounted. In addition, by folding back part of the display panel 6511 and arranging a connection portion with the FPC 6515 on the back side of the pixel portion, an electronic device with a narrow frame can be realized.

An example of a television device is shown in FIG. 22A. A television set 7100 has a display portion 7000 incorporated in a housing 7101 . Here, a configuration in which a housing 7101 is supported by a stand 7103 is shown.

The display device of one embodiment of the present invention can be applied to the display portion 7000 .

The operation of the television device 7100 shown in FIG. 22A can be performed using operation switches provided on the housing 7101 and a separate remote controller 7111 . Alternatively, the display portion 7000 may be provided with a touch sensor, and the television device 7100 may be operated by touching the display portion 7000 with a finger or the like. The remote controller 7111 may have a display section for displaying information output from the remote controller 7111 . A channel and a volume can be operated with operation keys or a touch panel provided in the remote controller 7111 , and an image displayed on the display portion 7000 can be operated.

Note that the television device 7100 is configured to include a receiver, a modem, and the like. The receiver can receive general television broadcasts. Also, by connecting to a wired or wireless communication network via a modem, one-way (from the sender to the receiver) or two-way (between the sender and the receiver, or between the receivers, etc.) information communication is performed. is also possible.

FIG. 22B shows an example of a notebook personal computer. A notebook personal computer 7200 has a housing 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, and the like. The display portion 7000 is incorporated in the housing 7211 .

An example of digital signage is shown in FIGS. 22C and 22D.

A digital signage 7300 shown in FIG. 22C includes a housing 7301, a display unit 7000, speakers 7303, and the like. Furthermore, it can have an LED lamp, an operation key (including a power switch or an operation switch), connection terminals, various sensors, a microphone, and the like.

FIG. 22D shows a digital signage 7400 attached to a cylindrical post 7401. A digital signage 7400 has a display section 7000 provided along the curved surface of a pillar 7401 .

The display device of one embodiment of the present invention can be applied to the display portion 7000 in FIGS. 22C and 22D.

The wider the display unit 7000, the more information can be provided at once. In addition, the wider the display unit 7000, the more conspicuous it is, and the more effective the advertisement can be, for example.

By applying a touch panel to the display unit 7000, not only can images or moving images be displayed on the display unit 7000, but also the user can intuitively operate the display unit 7000, which is preferable. Further, when used for providing information such as route information or traffic information, usability can be enhanced by intuitive operation.

Also, as shown in FIGS. 22C and 22D, the digital signage 7300 or digital signage 7400 is preferably capable of cooperating with an information terminal 7311 or information terminal 7411 such as a smartphone possessed by the user through wireless communication. For example, advertisement information displayed on the display unit 7000 can be displayed on the screen of the information terminal 7311 or the information terminal 7411 . By operating the information terminal 7311 or the information terminal 7411, display on the display portion 7000 can be switched.

Also, the digital signage 7300 or the digital signage 7400 can execute a game using the screen of the

information terminal

7311 or 7411 as an operation means (controller). This allows an unspecified number of users to simultaneously participate in and enjoy the game.

The electronic device shown in FIGS. 23A to 23F includes a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), connection terminals 9006, sensors 9007 (force, displacement, position, speed). , acceleration, angular velocity, number of rotations, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, smell, or infrared rays function), a microphone 9008, and the like.

The electronic devices shown in FIGS. 23A to 23F have various functions. For example, a function to display various information (still images, moving images, text images, etc.) on the display unit, a touch panel function, a calendar, a function to display the date or time, a function to control processing by various software (programs), It can have a wireless communication function, a function of reading and processing programs or data recorded on a recording medium, and the like. Note that the functions of the electronic device are not limited to these, and can have various functions. The electronic device may have a plurality of display units. In addition, even if the electronic device is equipped with a camera, etc., and has the function of capturing still images or moving images and storing them in a recording medium (external or built into the camera), or the function of displaying the captured image on the display unit, etc. good.

Details of the electronic devices shown in FIGS. 23A to 23F will be described below.

23A is a perspective view showing a mobile information terminal 9101. FIG. The mobile information terminal 9101 can be used as a smart phone, for example. Note that the portable information terminal 9101 may be provided with a speaker 9003, a connection terminal 9006, a sensor 9007, and the like. Also, the mobile information terminal 9101 can display text and image information on its multiple surfaces. FIG. 23A shows an example in which three icons 9050 are displayed. Information 9051 indicated by a dashed rectangle can also be displayed on another surface of the display portion 9001 . Examples of the information 9051 include notification of incoming e-mail, SNS, telephone call, title of e-mail or SNS, sender name, date and time, remaining battery power, radio wave intensity, and the like. Alternatively, an icon 9050 or the like may be displayed at the position where the information 9051 is displayed.

23B is a perspective view showing the mobile information terminal 9102. FIG. The portable information terminal 9102 has a function of displaying information on three or more sides of the display portion 9001 . Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different surfaces. For example, the user can confirm the information 9053 displayed at a position where the mobile information terminal 9102 can be viewed from above the mobile information terminal 9102 while the mobile information terminal 9102 is stored in the chest pocket of the clothes. The user can check the display without taking out the portable information terminal 9102 from the pocket, and can determine, for example, whether to receive a call.

FIG. 23C is a perspective view showing a wristwatch-type mobile information terminal 9200. FIG. The mobile information terminal 9200 can be used as a smart watch (registered trademark), for example. Further, the display portion 9001 has a curved display surface, and display can be performed along the curved display surface. The mobile information terminal 9200 can also make hands-free calls by mutual communication with a headset capable of wireless communication, for example. In addition, the portable information terminal 9200 can transmit data to and from another information terminal through the connection terminal 9006, and can be charged. Note that the charging operation may be performed by wireless power supply.

23D to 23F are perspective views showing a foldable personal digital assistant 9201. FIG. 23D is a perspective view of the portable information terminal 9201 in an unfolded state, FIG. 23F is a folded state, and FIG. 23E is a perspective view of a state in the middle of changing from one of FIGS. 23D and 23F to the other. The portable information terminal 9201 has excellent portability in the folded state, and has excellent display visibility due to a seamless wide display area in the unfolded state. A display portion 9001 included in the portable information terminal 9201 is supported by three housings 9000 connected by hinges 9055 . For example, the display portion 9001 can be bent with a curvature radius of 0.1 mm or more and 150 mm or less.

This embodiment can be appropriately combined with other embodiments.

100: display device, 100A: display device, 100B: display device, 101: layer, 110: pixel, 110a: sub-pixel, 110b: sub-pixel, 110c: sub-pixel, 110d: sub-pixel, 110d1: sub-pixel, 110d2: sub-pixel 110d3: sub-pixel 111: pixel electrode 111a: pixel electrode 111b: pixel electrode 111c: pixel electrode 111d: pixel electrode 112: conductive layer 112a: conductive layer 112b: conductive layer 112c: conductive layer, 113: layer, 114: layer, 115: common electrode, 118: sacrificial layer, 118A: sacrificial layer, 119: sacrificial layer, 119A: sacrificial layer, 120: substrate, 121: insulator, 122: resin layer, 123: Conductive layer, 123a: Conductive layer, 123b: Conductive layer, 124: Insulator, 124a: Insulator, 124A: Insulating film, 124b: Insulator, 124B: Insulating film, 125: Colored layer, 125a: Colored layer, 125b: colored layer, 125c: colored layer, 126: insulating layer, 128a: pixel, 128b: pixel, 130: light emitting device, 130a: light emitting device, 130b: light emitting device, 130c: light emitting device, 130d: light emitting device, 131: protective layer, 133: air gap, 140: connection portion, 142: adhesive layer, 148: light shielding layer, 151: substrate, 152: substrate, 162: display portion, 164: circuit, 165: wiring, 166: conductive layer, 172: FPC, 173: IC, 181a: hole injection layer, 181A: hole injection layer, 182a: hole transport layer, 182A: hole transport layer, 182b: hole transport layer, 182B: hole transport layer, 183a: Light-emitting layer, 183A: Light-emitting layer, 183b: Light-emitting layer, 183B: Light-emitting layer, 184a: Electron-transporting layer, 184A: Electron-transporting layer, 184b: Electron-transporting layer, 184B: Electron-transporting layer, 190: Resist mask, 191: Intermediate Layer 191A: Intermediate layer 192: Light emitting unit 194: Light emitting unit 201: Transistor 204: Connection part 205: Transistor 209: Transistor 210: Transistor 211: Insulating layer 213: Insulating layer 214: insulating layer, 215: insulating layer, 218: insulating layer, 221: conductive layer, 222a: conductive layer, 222b: conductive layer, 223: conductive layer, 225: insulating layer, 228: region, 231: semiconductor layer, 231i: channel Formation region 231n: Low resistance region 242: Connection layer 321: Insulating layer 331: Plug 362: Insulating layer 363: Insulating layer 364: Adhesive layer 400: Display device 400A: Display device 400B: Display device, 400C: display device, 401: substrate, 402: substrate, 410: transistor, 411: conductive layer, 412: low resistance region, 413: insulating layer, 414: insulating layer, 415: element isolation layer, 420: transistor , 421: semiconductor layer, 423: insulating layer, 424: conductive layer, 425: conductive layer, 426: insulating layer, 427: conductive layer, 428: insulating layer, 429: insulating layer, 432: insulating layer, 440: capacitive element , 441: conductive layer, 442: conductive layer, 443: insulating layer, 451: conductive layer, 452: conductive layer, 461: insulating layer, 461a: insulating layer, 461b: insulating layer, 462: insulating layer, 463: insulating layer , 465: insulating layer, 471: plug, 471a: conductive layer, 471b: conductive layer, 474: plug, 480: display module, 481: display section, 482: circuit section, 483: pixel circuit section, 483a: pixel circuit, 484: pixel portion, 484a: pixel, 485: terminal portion, 486: wiring portion, 490: FPC, 500: display device, 501: electrode, 502: electrode, 512Q_1: light emitting unit, 512Q_2: light emitting unit, 512Q_3: light emitting unit , 521: layer, 522: layer, 523Q_1: light-emitting layer, 523Q_2: light-emitting layer, 523Q_3: light-emitting layer, 524: layer, 525: layer, 531: intermediate layer, 540: protective layer, 545B: colored layer, 545G: colored Layer, 545R: colored layer, 550W: light emitting device, 6500: electronic device, 6501: housing, 6502: display unit, 6503: power button, 6504: button, 6505: speaker, 6506: microphone, 6507: camera, 6508: Light source 6510: Protective member 6511: Display panel 6512: Optical member 6513: Touch sensor panel 6515: FPC 6516: IC 6517: Printed circuit board 6518: Battery 7000: Display unit 7100: Television device , 7101: housing, 7103: stand, 7111: remote controller, 7200: notebook personal computer, 7211: housing, 7212: keyboard, 7213: pointing device, 7214: external connection port, 7300: digital signage, 7301: Case 7303: Speaker 7311: Information terminal 7400: Digital signage 7401: Pillar 7411: Information terminal 9000: Case 9001: Display unit 9003: Speaker 9005: Operation key 9006: Connection terminal, 9007: sensor, 9008: micro Phone, 9050: Icon, 9051: Information, 9052: Information, 9053: Information, 9054: Information, 9055: Hinge, 9101: Personal digital assistant, 9102: Personal digital assistant, 9200: Personal digital assistant, 9201: Personal digital assistant

Claims

a first light emitting device, a second light emitting device, a first colored layer, a second colored layer, a first insulator, a second insulator, and a third insulator; have
The first colored layer is arranged to overlap the first light emitting device,
The second colored layer is arranged to overlap the second light emitting device,
The first light emitting device and the second light emitting device have a function of emitting white light,
The first colored layer has a function of transmitting visible light of a color different from that of the second colored layer,
the first light emitting device having a first conductive layer and a first light emitting layer on the first conductive layer;
the second light emitting device having a second conductive layer and a second light emitting layer on the second conductive layer;
the first insulator is in contact with at least a portion of a side surface of the first light emitting device;
the second insulator is in contact with at least a portion of a side surface of the second light emitting device;
the first insulator and the second insulator are disposed over the third insulator;
the third insulator is disposed over an edge of the first conductive layer and an edge of the second conductive layer;
display device.
In claim 1,
The first light-emitting layer has the same material as the second light-emitting layer,
display device.
In claim 1 or claim 2,
The first light emitting device includes a first light emitting unit including the first light emitting layer, a first charge generation layer on the first light emitting unit, and a second charge generation layer on the first charge generation layer. and a light emitting unit of
The second light-emitting unit has a third light-emitting layer,
The second light-emitting device comprises a third light-emitting unit including the second light-emitting layer, a second charge generation layer on the third light-emitting unit, and a fourth charge generation layer on the second charge generation layer. and a light emitting unit of
The fourth light-emitting unit has a fourth light-emitting layer,
display device.
In claim 3,
the first light emitting unit has the same material as the third light emitting unit;
The first charge generation layer has the same material as the second charge generation layer,
the second light emitting unit has the same material as the fourth light emitting unit;
display device.
In claim 3 or claim 4,
the first light emitting unit has a first hole injection layer, a first hole transport layer, and a first electron transport layer;
the second light-emitting unit has a second hole-transporting layer and a second electron-transporting layer;
the third light-emitting unit has a second hole-injection layer, a third hole-transport layer, and a third electron-transport layer;
the fourth light-emitting unit has a fourth hole-transporting layer and a fourth electron-transporting layer;
The first insulator includes a side surface of the first hole injection layer, a side surface of the first hole transport layer, a side surface of the first light emitting layer, a side surface of the first electron transport layer, and a side surface of the first electron transport layer. in contact with a side surface of the first charge generation layer, a side surface of the second hole transport layer, a side surface of the third light emitting layer, and a side surface of the second electron transport layer;
The second insulator includes a side surface of the second hole injection layer, a side surface of the third hole transport layer, a side surface of the second light emitting layer, a side surface of the third electron transport layer, and a side surface of the third electron transport layer. abutting a side of the second charge generation layer, a side of the fourth hole transport layer, a side of the second light emitting layer, and a side of the fourth electron transport layer;
display device.
In any one of claims 1 to 5,
the first insulator and the second insulator having a first layer and a second layer on the first layer;
In the first insulator,
a side surface of the first layer contacts at least a portion of a side surface of the first light emitting device;
the bottom surface of the first layer is in contact with at least part of the third insulator;
the side surface and the bottom surface of the second layer are in contact with at least a portion of the first layer;
In the second insulator,
a side surface of the first layer contacts at least a portion of a side surface of the second light emitting device;
the bottom surface of the first layer is in contact with at least part of the third insulator;
the side and bottom surfaces of the second layer are in contact with at least a portion of the first layer;
display device.
In claim 6,
the first layer comprises aluminum oxide;
wherein the second layer comprises silicon nitride;
display device.
In any one of claims 1 to 7,
a side surface of the first light-emitting layer and a side surface of the second light-emitting layer face each other;
The distance between the side surface of the first light-emitting layer and the side surface of the second light-emitting layer is 8 μm or less,
display device.
a display device according to any one of claims 1 to 8;
and at least one of a connector and an integrated circuit.
a display module according to claim 9;
An electronic device comprising at least one of a housing, a battery, a camera, a speaker, and a microphone.